7 files changed, 31 insertions, 24 deletions
diff --git a/guides/source/action_mailer_basics.md b/guides/source/action_mailer_basics.md
index 92a4081233..bf3bf5d19e 100644
--- a/guides/source/action_mailer_basics.md
+++ b/guides/source/action_mailer_basics.md
@@ -344,7 +344,7 @@ The same format can be used to set carbon copy (Cc:) and blind carbon copy
 
 Sometimes you wish to show the name of the person instead of just their email
 address when they receive the email. The trick to doing that is to format the
-email address in the format `"Full Name <email>"`.
+email address in the format `"Full Name" <email>`.
 
 ```ruby
 def welcome_email(user)
diff --git a/guides/source/action_view_overview.md b/guides/source/action_view_overview.md
index 8a026cecac..950bb5e358 100644
--- a/guides/source/action_view_overview.md
+++ b/guides/source/action_view_overview.md
@@ -325,9 +325,9 @@ You can also render a block of code within a partial layout instead of calling `
 
 ```html+erb
 <% render(layout: 'box', locals: { article: @article }) do %>
-  <%= div_for(article) do %>
+  <div>
     <p><%= article.body %></p>
-  <% end %>
+  </div>
 <% end %>
 ```
 
diff --git a/guides/source/active_record_basics.md b/guides/source/active_record_basics.md
index 6551ba0389..a227b54040 100644
--- a/guides/source/active_record_basics.md
+++ b/guides/source/active_record_basics.md
@@ -74,8 +74,8 @@ By default, Active Record uses some naming conventions to find out how the
 mapping between models and database tables should be created. Rails will
 pluralize your class names to find the respective database table. So, for
 a class `Book`, you should have a database table called **books**. The Rails
-pluralization mechanisms are very powerful, being capable to pluralize (and
-singularize) both regular and irregular words. When using class names composed
+pluralization mechanisms are very powerful, being capable of pluralizing (and
+singularizing) both regular and irregular words. When using class names composed
 of two or more words, the model class name should follow the Ruby conventions,
 using the CamelCase form, while the table name must contain the words separated
 by underscores. Examples:
diff --git a/guides/source/association_basics.md b/guides/source/association_basics.md
index 412cfd198a..1fe111f2a0 100644
--- a/guides/source/association_basics.md
+++ b/guides/source/association_basics.md
@@ -590,7 +590,7 @@ If you create an association some time after you build the underlying model, you
 
 If you create a `has_and_belongs_to_many` association, you need to explicitly create the joining table. Unless the name of the join table is explicitly specified by using the `:join_table` option, Active Record creates the name by using the lexical order of the class names. So a join between customer and order models will give the default join table name of "customers_orders" because "c" outranks "o" in lexical ordering.
 
-WARNING: The precedence between model names is calculated using the `<` operator for `String`. This means that if the strings are of different lengths, and the strings are equal when compared up to the shortest length, then the longer string is considered of higher lexical precedence than the shorter one. For example, one would expect the tables "paper_boxes" and "papers" to generate a join table name of "papers_paper_boxes" because of the length of the name "paper_boxes", but it in fact generates a join table name of "paper_boxes_papers" (because the underscore '_' is lexicographically _less_ than 's' in common encodings).
+WARNING: The precedence between model names is calculated using the `<=>` operator for `String`. This means that if the strings are of different lengths, and the strings are equal when compared up to the shortest length, then the longer string is considered of higher lexical precedence than the shorter one. For example, one would expect the tables "paper_boxes" and "papers" to generate a join table name of "papers_paper_boxes" because of the length of the name "paper_boxes", but it in fact generates a join table name of "paper_boxes_papers" (because the underscore '\_' is lexicographically _less_ than 's' in common encodings).
 
 Whatever the name, you must manually generate the join table with an appropriate migration. For example, consider these associations:
 
@@ -620,7 +620,7 @@ class CreateAssembliesPartsJoinTable < ActiveRecord::Migration
 end
 ```
 
-We pass `id: false` to `create_table` because that table does not represent a model. That's required for the association to work properly. If you observe any strange behavior in a `has_and_belongs_to_many` association like mangled models IDs, or exceptions about conflicting IDs, chances are you forgot that bit.
+We pass `id: false` to `create_table` because that table does not represent a model. That's required for the association to work properly. If you observe any strange behavior in a `has_and_belongs_to_many` association like mangled model IDs, or exceptions about conflicting IDs, chances are you forgot that bit.
 
 ### Controlling Association Scope
 
@@ -793,7 +793,7 @@ If the associated object has already been retrieved from the database for this o
 
 ##### `association=(associate)`
 
-The `association=` method assigns an associated object to this object. Behind the scenes, this means extracting the primary key from the associate object and setting this object's foreign key to the same value.
+The `association=` method assigns an associated object to this object. Behind the scenes, this means extracting the primary key from the associated object and setting this object's foreign key to the same value.
 
 ```ruby
 @order.customer = @customer
@@ -1138,7 +1138,7 @@ If the associated object has already been retrieved from the database for this o
 
 ##### `association=(associate)`
 
-The `association=` method assigns an associated object to this object. Behind the scenes, this means extracting the primary key from this object and setting the associate object's foreign key to the same value.
+The `association=` method assigns an associated object to this object. Behind the scenes, this means extracting the primary key from this object and setting the associated object's foreign key to the same value.
 
 ```ruby
 @supplier.account = @account
@@ -1219,8 +1219,8 @@ Controls what happens to the associated object when its owner is destroyed:
 It's necessary not to set or leave `:nullify` option for those associations
 that have `NOT NULL` database constraints. If you don't set `dependent` to
 destroy such associations you won't be able to change the associated object
-because initial associated object foreign key will be set to unallowed `NULL`
-value.
+because the initial associated object's foreign key will be set to the
+unallowed `NULL` value.
 
 ##### `:foreign_key`
 
@@ -1506,7 +1506,9 @@ The `collection.where` method finds objects within the collection based on the c
 
 ##### `collection.exists?(...)`
 
-The `collection.exists?` method checks whether an object meeting the supplied conditions exists in the collection. It uses the same syntax and options as `ActiveRecord::Base.exists?`.
+The `collection.exists?` method checks whether an object meeting the supplied 
+conditions exists in the collection. It uses the same syntax and options as
+[`ActiveRecord::Base.exists?`](http://api.rubyonrails.org/classes/ActiveRecord/FinderMethods.html#method-i-exists-3F).
 
 ##### `collection.build(attributes = {}, ...)`
 
@@ -1617,9 +1619,10 @@ end
 
 By convention, Rails assumes that the column used to hold the primary key of the association is `id`. You can override this and explicitly specify the primary key with the `:primary_key` option.
 
-Let's say that `users` table has `id` as the primary_key but it also has
-`guid` column. And the requirement is that `todos` table should hold
-`guid` column value and not `id` value. This can be achieved like this
+Let's say the `users` table has `id` as the primary_key but it also
+has a `guid` column. The requirement is that the `todos` table should
+hold the `guid` column value as the foreign key and not `id`
+value. This can be achieved like this:
 
 ```ruby
 class User < ActiveRecord::Base
@@ -1627,8 +1630,8 @@ class User < ActiveRecord::Base
 end
 ```
 
-Now if we execute `@user.todos.create` then `@todo` record will have
-`user_id` value as the `guid` value of `@user`.
+Now if we execute `@todo = @user.todos.create` then the `@todo`
+record's `user_id` value will be the `guid` value of `@user`.
 
 
 ##### `:source`
@@ -2004,7 +2007,9 @@ The `collection.where` method finds objects within the collection based on the c
 
 ##### `collection.exists?(...)`
 
-The `collection.exists?` method checks whether an object meeting the supplied conditions exists in the collection. It uses the same syntax and options as `ActiveRecord::Base.exists?`.
+The `collection.exists?` method checks whether an object meeting the supplied
+conditions exists in the collection. It uses the same syntax and options as
+[`ActiveRecord::Base.exists?`](http://api.rubyonrails.org/classes/ActiveRecord/FinderMethods.html#method-i-exists-3F).
 
 ##### `collection.build(attributes = {})`
 
diff --git a/guides/source/contributing_to_ruby_on_rails.md b/guides/source/contributing_to_ruby_on_rails.md
index 39a9826f21..3279c99c42 100644
--- a/guides/source/contributing_to_ruby_on_rails.md
+++ b/guides/source/contributing_to_ruby_on_rails.md
@@ -66,7 +66,7 @@ the core team will have to make a judgement call. That said, the distinction
 generally just affects which release your patch will get in to; we love feature
 submissions! They just won't get backported to maintenance branches.
 
-If you'd like feedback on an idea for a feature before doing the work for make
+If you'd like feedback on an idea for a feature before doing the work to make
 a patch, please send an email to the [rails-core mailing
 list](https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core). You
 might get no response, which means that everyone is indifferent. You might find
@@ -79,17 +79,17 @@ discussions new features require.
 Helping to Resolve Existing Issues
 ----------------------------------
 
-As a next step beyond reporting issues, you can help the core team resolve existing issues. If you check the [Everyone's Issues](https://github.com/rails/rails/issues) list in GitHub Issues, you'll find lots of issues already requiring attention. What can you do for these? Quite a bit, actually:
+As a next step beyond reporting issues, you can help the core team resolve existing issues. If you check the [issues list](https://github.com/rails/rails/issues) in GitHub Issues, you'll find lots of issues already requiring attention. What can you do for these? Quite a bit, actually:
 
 ### Verifying Bug Reports
 
 For starters, it helps just to verify bug reports. Can you reproduce the reported issue on your own computer? If so, you can add a comment to the issue saying that you're seeing the same thing.
 
-If something is very vague, can you help squash it down into something specific? Maybe you can provide additional information to help reproduce a bug, or help by eliminating needless steps that aren't required to demonstrate the problem.
+If an issue is very vague, can you help narrow it down to something more specific? Maybe you can provide additional information to help reproduce a bug, or help by eliminating needless steps that aren't required to demonstrate the problem.
 
 If you find a bug report without a test, it's very useful to contribute a failing test. This is also a great way to get started exploring the source code: looking at the existing test files will teach you how to write more tests. New tests are best contributed in the form of a patch, as explained later on in the "Contributing to the Rails Code" section.
 
-Anything you can do to make bug reports more succinct or easier to reproduce is a help to folks trying to write code to fix those bugs - whether you end up writing the code yourself or not.
+Anything you can do to make bug reports more succinct or easier to reproduce helps folks trying to write code to fix those bugs - whether you end up writing the code yourself or not.
 
 ### Testing Patches
 
@@ -117,7 +117,7 @@ Once you're happy that the pull request contains a good change, comment on the G
 
 >I like the way you've restructured that code in generate_finder_sql - much nicer. The tests look good too.
 
-If your comment simply says "+1", then odds are that other reviewers aren't going to take it too seriously. Show that you took the time to review the pull request.
+If your comment simply reads "+1", then odds are that other reviewers aren't going to take it too seriously. Show that you took the time to review the pull request.
 
 Contributing to the Rails Documentation
 ---------------------------------------
diff --git a/guides/source/debugging_rails_applications.md b/guides/source/debugging_rails_applications.md
index a3c16c7660..96bf532868 100644
--- a/guides/source/debugging_rails_applications.md
+++ b/guides/source/debugging_rails_applications.md
@@ -778,7 +778,7 @@ will be stopped and you will have to start it again.
 
 ### Settings
 
-`byebug` has a few available options to tweak its behaviour:
+`byebug` has a few available options to tweak its behavior:
 
 * `set autoreload`: Reload source code when changed (defaults: true).
 * `set autolist`: Execute `list` command on every breakpoint (defaults: true).
diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md
index 3680055f0c..17309d4b47 100644
--- a/guides/source/upgrading_ruby_on_rails.md
+++ b/guides/source/upgrading_ruby_on_rails.md
@@ -940,6 +940,8 @@ Please read [Pull Request #9978](https://github.com/rails/rails/pull/9978) for d
 
 * Rails 4.0 has removed the XML parameters parser. You will need to add the `actionpack-xml_parser` gem if you require this feature.
 
+* Rails 4.0 changes the default `layout` lookup set using symbols or procs that return nil. To get the "no layout" behavior, return false instead of nil. 
+
 * Rails 4.0 changes the default memcached client from `memcache-client` to `dalli`. To upgrade, simply add `gem 'dalli'` to your `Gemfile`.
 
 * Rails 4.0 deprecates the `dom_id` and `dom_class` methods in controllers (they are fine in views). You will need to include the `ActionView::RecordIdentifier` module in controllers requiring this feature.