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The latest version of the book is P5.0, released almost 6 years ago. If you've bought a PDF of the book and would like to update it to this version (for free), visit your home page.

By default this page displays the errata for the latest version of the book. If you have a previous version, select it here:

If you've found a new error, please submit it.

  • Typo
  • Tech. error
  • Suggestion
  • Maybe next edition
  • Not a problem
  • Reported in: P5.0 (12-Sep-15)
Paper page: 20
Sorry the page number is incorrect - i am reading using the kindle cloud reader. Two serious issues: (1) the author's email address needs to be ...more...
  • Reported in: P4.0 (04-Nov-19)
Paper page: 51
In the 2nd paragraph from the bottom, the last sentence is "(Even if we were to set flavor to point to something else later in the program, that would...more...
  • Reported in: P5.0 (04-Jun-15)
PDF page: 61
Chapter on Methods does not use the community accepted Ruby Style Guide of encasing parameters in parenthesis. Parenthesis are only left off of method...more...
  • Reported in: P5.0 (10-May-16)
PDF page: 64
It seems like the blank lines that are present in the representation of screen output disappear in the epub version of the text. For example, in the p...more...
  • Reported in: P4.0 (03-Mar-14)
Paper page: 66
In the method 'ask' the answer variables are declared in the private scope of an 'if' then used later as the return at which point it is inaccessible....more...
  • Reported in: P4.0 (12-Oct-13)
PDF page: 87

Text halfway down page reads "Viola!" While this is a recognized English word, it ought to read "Voila!"--Luke

  • Reported in: P4.0 (26-Oct-13)
PDF page: 116

". However, none of these is actually called until the very last line.)"

Shouldn't it be "none of these are"?

  • Reported in: P5.0 (13-Jan-16)
PDF page: 141
The answer ("How I would do it") to the "modern roman numeral" question was "MIM", when it should be "MCMXCIX", which represents the year 1999 as in "...more...