**From the poet laureate of medicine and national bestselling author of *Awakenings* comes a fascinating investigation of Southern Mexico that explores the origins of chocolate and mescal, pre-Columbian culture and hallucinogens, and the peculiar passions of botanists. • A delightful work. — *San Francisco Chronicle* ** Since childhood, Oliver Sacks has been fascinated by ferns: an ancient class of plants able to survive and adapt in many climates. Along with a delightful group of fellow fern aficionados—mathematicians, poets, artists, and assorted botanists and birders—he embarks on an exploration of Southern Mexico, a region that is also rich in human history and culture. What other species would comb ancient Zapotec ruins on their hands and knees, searching for a new type of fern? Combining Sacks’s enthusiasm for natural history and the richness of humanity with his sharp and observant eye for detail, *Oaxaca Journal* is a rare treat.