This subseries contains research files on HIV/AIDS, safe sex advocacy, gay rights issues; and other topics of interest to Berkowitz, most of which was used in his writings. The files contain paper and born-digital materials, including newspaper and magazine clippings, books, pamphlets, fliers, audio recordings, correspondence, and notes. Berkowitz's collaborations with Michael Callen, Michelle Cochrane, Celia Farber, and Joseph Sonnabend are documented in audio recordings of their conversations, notes on the conversations, drafts of articles by Cochrane and Farber, and email and internet chats between Berkowitz and Farber.