Sacks, a neurologist and author of the popular The Man Who Mistook His Wife for a Hat ( LJ 2/15/86), developed a serious interest in sign language and deafness after reviewing Harlan Lane's When the Mind Hears ( LJ 10/15/84 ) for the New York Review of Books . In this work, Sacks explores all facets of the deaf world--he meets with deaf people and their families and visits schools for the deaf, spending a good deal of time at Gallaudet University. As he writes, "I had now to see them in a new, 'ethnic light,' as people with a distinctive language, sensibility, and culture of their own." The work is divided into three broad sections, throughout which there are numerous, somewhat distracting footnote "excursions." Although there is a wealth of insight and information here, the book tends to drag for the average reader and may disappoint fans of Sacks's previous best seller. Recommended for scholars and graduate collections. - Debra Berlanstein, Towson State Univ., Baltimore