Dubbed “Mensa’s evil twin” by The New York Times, The Master Theorem originated in 2011 as an online “secret society of solvers” and quickly developed a cult following. Its larger-than-life figurehead was the cryptic polymath known only as M who posted mysterious puzzles, called Theorems, each week at midnight.

After an eight-year sabbatical, M dramatically re-emerged with a beautifully illustrated puzzle book that features fully revamped versions of his old classics, plus an assortment of new puzzles and other enigmatic surprises. With five new “training” puzzles and plenty of hints in the back, the book is sure to captivate the attention of both old and new TMT fans alike.

M’s Theorems are not your average Sudoku or crossword puzzles. They’re each completely unique, beautifully illustrated, “escape room”-like puzzles that’ll have you decrypting messages and tackling creative brain-teasers. Solvers will enjoy weeks to months of neuron-growing entertainment as they work their way through M’s 40+ perplexing puzzles and become experts in codes, ciphers, and the mysteries of the universe.