Update book links to amazon affiliate shortened links.

trails/grids.md

@@ -4,16 +4,16 @@ Grids
 Critical learning
 -----------------
 
-* Read [Grid Systems: Principles of Organizing Type](http://amzn.to/7A1Dn).
-* Read [Grid Systems in Graphic Design](http://amzn.to/11anRS).
+* Read [Grid Systems: Principles of Organizing Type](http://amzn.to/grid-systems-principles). ($)
+* Read [Grid Systems in Graphic Design](http://amzn.to/grid-systems-graphic-design). ($)
 * Read Mark Boulton's "Designing Grid Systems":
   * [1](http://goo.gl/VOGP)
   * [2](http://goo.gl/at66)
   * [3](http://goo.gl/pw0Ks)
   * [4](http://goo.gl/EnL22)
   * [5](http://goo.gl/s9L1y)
-* Read [Ordering Disorder: Grid Principles for Web Design](http://amzn.com/0321703537).
-* Read [Geometry of Design: Studies in Proportion and Composition](http://amzn.com/1568982496).
+* Read [Ordering Disorder: Grid Principles for Web Design](http://amzn.to/ordering-disorder). ($)
+* Read [Geometry of Design: Studies in Proportion and Composition](http://amzn.to/geometry-design). ($)
 
 Validation
 ----------

trails/html.md

@@ -7,7 +7,7 @@ Critical learning
 * Read [A Beginner’s Guide to HTML & CSS](http://learn.shayhowe.com/).
 * Complete [Code Academy Web Fundamentals](http://www.codecademy.com/tracks/web).
 * Read [Dive into HTML5](http://diveintohtml5.info/).
-* Read [HTML5 for Web Designers](http://www.abookapart.com/products/html5-for-web-designers).
+* Read [HTML5 for Web Designers](http://www.abookapart.com/products/html5-for-web-designers). ($)
 
 Validation
 ----------

trails/information-design.md

@@ -4,10 +4,10 @@ Information Design
 Critical learning
 -----------------
 
-* Read [Information Dashboard Design](http://amzn.to/6njM).
-* Read [Envisioning Information](http://amzn.to/YVYei).
-* Read [The Visual Display of Quantitative Information](http://amzn.to/SKnya8).
-* Read [A Practical Guide to Designing with Data](http://www.fivesimplesteps.com/products/a-practical-guide-to-designing-with-data).
+* Read [Information Dashboard Design](http://amzn.to/information-dashboard). ($)
+* Read [Envisioning Information](http://amzn.to/envisioning-information). ($)
+* Read [The Visual Display of Quantitative Information](http://amzn.to/visual-display). ($)
+* Read [A Practical Guide to Designing with Data](http://www.fivesimplesteps.com/products/a-practical-guide-to-designing-with-data). ($)
 
 Validation
 ----------

trails/ios.md

@@ -5,11 +5,11 @@ Critical Learning
 -----------------
 
 * Read [Learning Objective-C: A Primer](http://developer.apple.com/library/mac/#referencelibrary/GettingStarted/Learning_Objective-C_A_Primer/_index.html)
-* Read [Learn Objective-C on the Mac](http://www.amazon.com/Learn-Objective-C-Mac-For-Apress/dp/1430241888/ref=sr_1_1?s=books&ie=UTF8&qid=1339042063&sr=1-1) ($)
-* Read [Beginning iOS 5 Development: Exploring the iOS SDK](http://www.amazon.com/Beginning-iOS-Development-Exploring-SDK/dp/1430236051/ref=sr_1_2?ie=UTF8&qid=1339041976&sr=8-2) ($)
+* Read [Learn Objective-C on the Mac](http://amzn.to/learn-objective-c-mac) ($)
+* Read [Beginning iOS 5 Development: Exploring the iOS SDK](http://amzn.to/beginning-ios5) ($)
 * Read [The Objective-C Programming Language](http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/ObjectiveC/Introduction/introObjectiveC.html)
 * Read [About Memory Management](https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/MemoryMgmt/Articles/MemoryMgmt.html)
-* Read chapters 6 - 15, 17 - 19, 24, 28 - 30 of [Cocoa Design Patterns](http://www.amazon.com/Cocoa-Design-Patterns-Erik-Buck/dp/0321535022/ref=sr_1_1?s=books&ie=UTF8&qid=1339033714&sr=1-1) ($)
+* Read chapters 6 - 15, 17 - 19, 24, 28 - 30 of [Cocoa Design Patterns](http://amzn.to/cocoa-design-patterns) ($)
 * Read and hack on [sample code](https://developer.apple.com/library/ios/navigation/#section=Resource%20Types&topic=Sample%20Code)
 * Read the [Mobile Human Interface Guidelines](http://developer.apple.com/library/ios/#documentation/UserExperience/Conceptual/MobileHIG/Introduction/Introduction.html)
 

trails/javascript.md

@@ -6,7 +6,7 @@ Critical learning
 
 * Complete [Codecademy](http://www.codecademy.com) exercises.
 * Read [Eloquent Javascript](http://eloquentjavascript.net/contents.html).
-* Read [Javascript Web Applications](http://amzn.to/NXIp5t).
+* Read [Javascript Web Applications](http://amzn.to/javascript-web-apps). ($)
 
 Validation
 ----------

trails/refactoring.md

@@ -34,5 +34,5 @@ You know advanced refactoring when you can (safely):
 Ongoing reference
 -----------------
 
-* [Refactoring: Ruby Edition](http://www.amazon.com/Refactoring-Ruby-Edition-ebook/dp/B002TIOYWG/ref=kinw_dp_ke?ie=UTF8&m=AG56TWVU5XWC2) ($)
-* [Refactoring to Patterns](http://www.amazon.com/Refactoring-to-Patterns-ebook/dp/B001TKD4RQ/ref=kinw_dp_ke?ie=UTF8&m=AG56TWVU5XWC2) ($)
+* [Refactoring: Ruby Edition](http://amzn.to/ruby-refactoring) ($)
+* [Refactoring to Patterns](http://amzn.to/refactoring-to-patterns) ($)

trails/ruby.md

@@ -6,11 +6,11 @@ Critical Learning
 
 * First, [Try Ruby](http://tryruby.org)!
 * Read [Learn Ruby The Hard Way](http://ruby.learncodethehardway.org/book/).
-* Read [The Well-Grounded Rubyist](http://manning.com/black2/). ($)
+* Read [The Well-Grounded Rubyist](http://amzn.to/grounded-rubyist). ($)
 * Complete the [Ruby Koans](http://rubykoans.com).
 * Read examples of source code, such as [this](https://github.com/jferris/effigy/tree/master/lib).
 * Read these sections of
-  [The Pickaxe](http://pragprog.com/book/ruby/programming-ruby): ($)
+ [The Pickaxe](http://amzn.to/pickaxe-19): ($)
 
 ```shell
 Chapter 23, "Duck Typing"

trails/rubymotion.md

@@ -6,7 +6,7 @@ Critical Learning
 
 * Complete the [Ruby](/thoughtbot/trail-map/blob/master/trails/ruby.md) trail.
 * Complete the [iOS](/thoughtbot/trail-map/blob/master/trails/ios.md) trail.
-* [Purchase RubyMotion](http://sites.fastspring.com/hipbyte/product/rubymotion).
+* [Purchase RubyMotion](http://sites.fastspring.com/hipbyte/product/rubymotion). ($)
 * Complete the [Getting Started](http://goo.gl/FAMxA) guide.
 * Watch the Pragmatic Programmers'
   [RubyMotion video](http://pragmaticstudio.com/screencasts/rubymotion).

trails/test-driven-development.md

@@ -4,7 +4,7 @@ Test-Driven Development
 Critical learning
 -----------------
 
-* Read [Test-Driven Development By Example](http://www.amazon.com/Test-Driven-Development-By-Example/dp/0321146530). ($)
+* Read [Test-Driven Development By Example](http://amzn.to/test-driven-dev). ($)
 * Read [Beginning Outside-In Rails Development with Cucumber and RSpec](http://blog.carbonfive.com/2012/02/14/beginning-outside-in-rails-development-with-cucumber-and-rspec/).
 * Read [Martin Fowlers "Mocks Aren't Stubs"](http://martinfowler.com/articles/mocksArentStubs.html).
 
@@ -24,4 +24,4 @@ You know everyday TDD when you can:
 Ongoing reference
 -----------------
 
-* [xUnit Test Patterns](http://xunitpatterns.com)
+* [xUnit Test Patterns](http://amzn.to/x-test-patterns) ($)

trails/typography.md

@@ -4,14 +4,14 @@ Typography
 Critical learning
 -----------------
 
-* Read [The Elements of Typographic Style](http://amzn.to/aRAKml) and
+* Read [The Elements of Typographic Style](http://amzn.to/elements-typographic-style) ($) and
   [how it applies to the web](http://webtypography.net).
-* Read [Thinking with Type](http://amzn.to/U76Kbj).
+* Read [Thinking with Type](http://amzn.to/thinking-with-type).
 * Read [Real Web Type in Real Web Context](http://www.alistapart.com/articles/real-web-type-in-real-web-context/).
 * Read [On Web Typography](http://www.alistapart.com/articles/on-web-typography/).
 * Read [More Meaningful Typography](http://www.alistapart.com/articles/more-meaningful-typography/).
 * Watch [Tim Brown's More Perfect Typography](https://vimeo.com/17079380).
-* Read [Stop Stealing Sheep & Find Out How Type Works](http://amzn.com/0201703394).
+* Read [Stop Stealing Sheep & Find Out How Type Works](http://amzn.to/stop-stealing-sheep). ($)
 
 Validation
 ----------

trails/unix.md

@@ -4,7 +4,7 @@ Unix
 Critical learning
 -----------------
 
-* Read [The Linux Programming Interface](http://www.amazon.com/The-Linux-Programming-Interface-Handbook/dp/1593272200) Chapters 1,2,6,8,10,14,15,18,25,44,62. ($)
+* Read [The Linux Programming Interface](http://amzn.to/the-linux-programming-interface). ($) Chapters 1,2,6,8,10,14,15,18,25,44,62.
 * Read about [I/O redirection](http://en.wikipedia.org/wiki/Redirection_%28computing%29).
 
 Validation

trails/visual-design.md

@@ -4,15 +4,15 @@ Visual Design
 Critical learning
 -----------------
 
-* Read [Visual Grammar](http://amzn.to/aT3zuv).
-* Read [Universal Principles of Design](http://amzn.to/NYddly).
+* Read [Visual Grammar](http://amzn.to/visual-grammar). ($)
+* Read [Universal Principles of Design](http://amzn.to/universal-principles). ($)
 * Read Andy Rutledge's "Gestalt Principles":
   * [1](http://www.andyrutledge.com/gestalt-principles-1-figure-ground-relationship.php)
   * [2](http://www.andyrutledge.com/gestalt-principles-2-similarity.php)
   * [3](http://www.andyrutledge.com/gestalt-principles-3.php)
   * [4](http://www.andyrutledge.com/common-fate.php)
   * [5](http://www.andyrutledge.com/closure.php)
-* Read [101 Things I Learned in Architecture School](http://amzn.com/0262062666)
+* Read [101 Things I Learned in Architecture School](http://amzn.to/101-things-learned) ($)
 
 Validation
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