• Beta 5 includes all of the chapters in the final book, adding Chapter 26, “Types, Types, Types! Modeling Lambda Calculus,” and Chapter 27, “The Halting Problem.”

• Corrections to all outstanding errata as of March 27th.

• Stylistic corrections to chapters 1 through 4.

Beta 4 includes two new chapters on lambda calculus: Chapter 24, “Calculus: No not that calculus, lambda calculus!” and Chapter 25, “Numbers, Booleans, and Recursion, Oh my!”

Many revisions to earlier chapters, including corrections to all outstanding errata as of March 13.

• Beta 3 includes two new chapters: Chapter 23, “The Turing Machine” and Chapter 24, “Pathology and the Heart of Computing.”

• We’ve also fixed all errata reported by readers as of February 15th.

• We’ve added a new chapter, Chapter 21, “Finite State Machines.”
• At the request of readers, we have added chapter numbers.
• We’ve fixed all errata reported by readers as of January 29.

Initial beta release.