For artist Wolfgang Tillmans, portraiture is a collaborative process between photographer and accomplice. While Tillmans' photographs are often referred to as casual, they are actually the result of a carefully constructed process of engagement with his models. Each sitter, be they a world-famous rock star or a family member, projects both vulnerability and dignity. Presented here are a selection of some of the best of these portraits, taken between 1988 to 2001, and chosen by Tillmans himself. Subjects include filmmaker John Waters, architect Rem Koolhaas, musicians Moby and Michael Stipe, actresses Irm Hermann and Chloë Sevigny, as well as the artist's family and friends.