Understanding Computation: Preface, Just Enough Ruby

Understanding Computation
From Simple Machines to Impossible Programs
by Tom Stuart

Homepage: http://computationbook.com
Sample: http://computationbook.com/sample
Source Code: https://github.com/tomstuart/computationbook
Amazon (US): http://www.amazon.com/dp/1449329276
Amazon (UK): http://www.amazon.co.uk/dp/1449329276
Kindle: http://www.amazon.com/Understanding-Computation-Machines-Impossible-Programs-ebook/dp/B00CT3C4IM/ref=tmm_kin_title_0?_encoding=UTF8&sr=&qid=
O'Reilly: http://shop.oreilly.com/product/0636920025481.do

Readers:
Justin Campbell
Amy Unger
Ashton Harris
Brian Cobb

Discussions:
Preface, Just Enough Ruby
Chapter 2: The Meaning of Programs, Operational Semantics
Chapter 2: Denotational Semantics, Formal Semantics in Practice, Implementing Parsers
Chapter 3: The Simplest Computers
Chapter 4: Just Add Power
Chapter 5: The Ultimate Machine
Chapter 6: Programming with Nothing
Chapter 7: Universality is Everywhere
Chapter 8: