Interspersed with autobiographical observations, Jennifer Ackerman's Sex Sleep Eat Drink Dream: A Day in the Life of Your Body is both a personal and generalized tour of the human body. Ackerman's work is fascinating, and it's easy to focus on the parts that most interest the reader like, why can't I sleep at night? (It might be just part of the aging process.) Or, what makes that woman so attractive? (A direct gaze, symmetrical face, full lips and dilated pupils.) But the whole book is worth investigating for its explorations of appetite, sexual urges and nightmares, among other distinctly human experiences and expressions. The book is divided into times of day morning, midday, afternoon, evening and night and then subdivided into germane topics. The system of organization works well because it keeps readers conscious of the rhythms of the body, so formed by the rhythms of the day. The section on Wit, for example, is in the morning part of the book, when many of us are sharpest, and a section on how we interpret different faces is in the Dusk portion, when many people attend parties or other social events. The Afternoon section includes The Doldrums and In Motion, encompassing both the torpor and production that the post-lunch period seems to engender. Ackerman's latest is full of intriguing facts, including that coffee's flavor is 75 percent due to its odor. Jaws can put as much as 128 pounds of pressure on teeth during chewing. Laughter rouses the brain's most primal reward circuits, which is how it relieves stress. Regular moderate exercise may relieve the symptoms of depression as well as therapy, and humans are the only species that can override the body's natural sequence at will, forcing ourselves to stay awake, or denying hunger pangs. Sex Sleep Eat Drink Dream offers fascinating insight into the workings of our often inscrutable bodies. It's also amazingly comprehensive. As Ackerman writes, From caress to orgasm, multitasking to memorizing, working out to stressing out, drooping to dreaming, it's here.