Best Ruby & Rails books

After reaching to 100+ books in my Ruby and Rails library, here are some hints about what the best books about Ruby & Rails might be (a matter of personal taste, of course):

0. General

• The Passionate Programmer (2nd edition), by Chad Fowler
• The Productive Programmer, by Neal Ford

1. Plain Ruby

• Programming Ruby (aka "The pickaxe book", 3rd edition), by Dave Thomas
• The Ruby Programming Language, by David Flanagan and Yukihiro Matsumoto (aka Matz)

2.a Plain Sinatra

• Jump Start Sinatra, by Darren Jones
• Sinatra Up and Running, by Alan Harris and Konstantin Haase

2.b Plain Rails

• Agile Web Development with Rails (4th edition), by Sam Ruby, Dave Thomas and David Heinemeier Hansson (aka DHH)
• Learning Rails 3, by Simon St. Laurent, Edd Dumbill and Eric J. Gruber

3. Advanced Ruby

• Design Patterns in Ruby, by Russ Olsen
• Eloquent Ruby, by Russ Olsen

4. Advanced Rails

• The Rails 3 Way, by Obie Fernandez
• Rails Antipatterns, by Chad Pytel and Tammer Sale

Web references:

http://pragprog.com/

http://oreilly.com/

http://www.sitepoint.com/

http://www.informit.com/