Page 106 should read:
"blocks are akin to 'partial' or 'unborn' Procs and need the lambda method to be made into full fledged Procs"

instead of:

"blocks are akin to 'partial' or 'unborn' blocks and need the lambda method to be made into full fledged Procs"

Page 130 should read:
"Our tests showed that the simple fibonacci1.rb took about 6.20 seconds to run 5 successive operations of calling fib on the number 30."

instead of:

"Our tests showed that the simple fibonacci1.rb took about 6.20 seconds to run 30 consecutive operations of calling fib on the numbers from one to five."

Script Update: Some users on Windows have experienced difficulty with the understand_args? method in simple_cli.rb from script #7, wherein the default condition is not triggered. If you experience this problem, try replacing the line

OPTIONS.keys.any? { |key| OPTIONS[key].include?(args[0])

with

(not args[0]) || OPTIONS.keys.any? { |key| OPTIONS[key].include?(args[0]) }

Thanks to Gene Temple for finding this bug and proposing a solution.

File Update:  The original radio_player2.rb script has a small bug that reports incorrect start times for the files. You can download an updated version here. (Note: The .zip and .bz2 archives on the main page were updated to include this file on 9/19/07.)

Page 90, "The Results":
The phrase "returned value from output_rates..." should read "returned value from puts"

Page 131, IRB Example:
The period after 'wall.empty?' should be removed in the execution example.

Page 248, under "Dissecting the ApplicationHelper":
Edit app/helpers/application.rb to match the following:" should read, "Edit app/helpers/application_helper.rb to match the following:"

Page 257:
In the last sentence under "Using CSS," the show.css stylesheet is mistakenly called public.css. The sentence should read, "The stylesheets master.css, show.css, and index.css are available for download at this book's website."