London-based designer Thomas Thwaites is a free spirit with the soul of an engineer. He tackles zany projects by applying established principles and a sense of humor. His new book is “GoatMan: How I Took a Holiday From Being Human’’ (Princeton Architectural). Thwaites is an amiable storyteller whose account is accompanied by dozens of photographs of his adventures. To mimic a goat’s life, he acquired prosthetic goat legs and a contraption — modeled on a goat stomach — that digested the grass he ate. He spent several days ambling around the Swiss Alps with a goat herd, before quitting the experiment and retreating to a farmhouse.

JAN GARDNER