On the history and creation of ambigrams, by a pioneer of the practice  “Spellbinding and truly one-of-a-kind. . . . This is an absolute delight.”—Publishers Weekly (starred review)  In the 1960s and 1970s, a trio of imaginative individuals independently discovered that ordinary words and phrases could be given double readings by playfully distorting the letters composing them. These doubly readable words and phrases, if designed by an artistic eye and hand, could possess great visual beauty. Douglas Hofstadter named such calligraphic creations “ambigrams,” and over the decades he has designed thousands of them, as have his friends Scott Kim and John Langdon, the other main pioneers of the subtle art form he calls ambigrammia. ABCD (Hofstadter’s informal title for this book) offers a sampler of hundreds of Hofstadter’s ambigrams, along with a few dozen by Kim, Langdon, and others.  With deep links to cognitive science, ABCD exhibits ambigrams of many types and shows how ambigrammia can be extended in surprising directions. All along the way, Hofstadter discusses creativity and its alter ego, “discoverativity,” revealing how the “pocket sized creativity puzzles” that constitute the art form are pervaded by these complementary qualities. ABCD is also notably autobiographical: Hofstadter vividly recounts how his life has been intimately intertwined with the creation/discovery of ambigrams in many countries and in many languages.