Gender identity isn’t something openly discussed and studied as a shaping force in the arts (or , until recently, in science, for that matter), but it is a powerful one. Hide/Seek: Difference and Desire in American Portraiture takes an ambitious look at the history of sexual difference, published as a companion volume to a Smithsonian exhibition of the same title, but offering a powerful stand-alone piece of visual scholarship charting the hidden impact of gay and lesbian artists on the history of art and portraiture and how they explored the fluidity of gender and sexuality.

The book explores the presence and evolution of same-sex desire in contemporary portraiture through more than 140 full-color drawings, illustrations and photographs by prominent American artists, from Georgia O’Keeffe to Jasper Johns to Andy Warhol. (Including a remarkable silver print of Susan Sontag, with whom I’m hopelessly obsessed.)

A historical account contextualizes the artwork, tracing the influential marginality of LGBT artists from the turn of the 20th century to the gay liberation movement of 1969 to the AIDS epidemic of the 80s to today.

Hide/Seek comes from authors Jonathan D. Katz, founder of the first department for gay and lesbian studies in the US, and National Portrait Gallery historian David C. Ward. It is both a brilliantly curated anthology of seminal portraiture and an essential piece of cultural history for human rights and equality.