Acknowledgments

I thank my friend Miki Tebeka, who invited me to write this book, albeit in slightly different form than the version you see. I am very grateful to my friend Brad Huntting and partner Mary Ann Sushinsky who provided clever ideas in the directions of these puzzles. Thanks to my colleague Lucy Wan, who provided a final proofreading, finding the many silly typos missed on many prior reads.

A number of other friends and family members listened to me enumerate the foibles of another publisher who clings to a cargo-culted toolchain.

With ambivalence, I thank Noam Chomsky for arranging computability into a neat hierarchy, with regular expressions at the bottom.