5 books every app developer should read

I can tell what kind of developer you are if you tell me what are your favorite development books. What can you tell about me? Here are my favorites:

1. Getting real by 37signals
   

   If I could recommend a single book, Getting Real would be my choice.
   This was the book that helped me understand that software development can be done so much better.
   It is a revelation.

2. Universal principles of design by William Lidwell
   

   If you want to understand why some designs are great and why some suck you need to read this book. Not only once, but again and again.
   This book should be kept on your desk.
   It is the times table for designers.

3. Design patterns by Erich Gamma & Co
   

   This book is one of the Object oriented programming cornerstones. It is invaluable if you need to design relations between objects in code. Unless you have one or two object types in your apps, you need to read this book.

4. Envisioning information by Edward R. Tufte
   

   After you read this book you have the feeling that whatever you chosen to display information in your app, you could have done better, that you can use something more simple and elegant.
   It can be shocking how many alternatives are out there.

5. Mac OS X Human Interface Guidelines by Apple
   

   If you ever need to create an app for the Mac, read the HIG.
   If you ever need to create an app for iPhone or iPad read the iOS HIG.
   Yep, Apple tells you how to create great apps for their great hardware.