First published in 2009, this biography of Masters and Johnson has been reissued as the TV series it inspired is aired. Maier offers a fascinating insight into the origins of America's sexual revolution. Masters was a brilliant obstetrician-gynecologist. But the droll, bow-tied medic risked professional ruin by studying human sexuality in the 1950s when even the word "pregnant" could be bleeped from TV programmes. Initially he observed prostitutes, telling the chancellor of his university they "are the only experts on the subject of sex that I can identify". Later he gathered physiological data using volunteers who performed sex acts with paper bags on their heads. He hired the medically unqualified Johnson as a secretary, who quickly became indispensable: it was "as if she'd found her life's vocation". Shockingly, Maier reveals Masters made it plain to her that being his sexual partner was "part of the job". Their books weren't racy ("stimulative approach opportunity" was code for foreplay) but soon became bestsellers, and their science-based view of sex changed people's attitudes and lives. Maier's muscular narrative is sometimes trite but always compelling.