Composer, singer, writer and AIDS activist. Played a major role in shaping the United States response to the AIDS epidemic. Callen was an AIDS activist before there was an AIDS movement, involved in virtually all of the positive responses to the epidemic, including the self-empowerment of People with AIDS; the invention of safer sex; the community-based research movement; development of prophylaxis for major opportunistic infections; and the establishment of buyer's clubs providing low-cost access to both experimental and approved AIDS treatments. Callen was a founding board member of the People with AIDS Coalition, the Community Research Initiative, the National Association of People with AIDS, the PWA Health Group, the New York City Mayor's Interagency Task Force on AIDS, and the New York State AIDS Institute. He testified before the President's Commission on AIDS, the U.S. Senate and House of Representatives, the New York State Legislature, the New York City Council and the Australian AIDS Council. He was a noted and influential writer on AIDS, writing a myriad of books concerning the matter. His book, Surviving AIDS, published by Harper/Collins in 1990, received honorable mention from the American Medical Writers Association. Through appearances on various news shows, such as Nightline, Good Morning America, 20/20 and a variety of talk shows, such as The Phil Donahue Show and Geraldo, Callen gave AIDS a human face. He also appeared in several films and documentaries, including the Hollywood AIDS movie Philadelphia and the HBO documentary "Why Am I Gay?" Callen also sang in John Greyson's movie "Zero Patience". Callen's work was recognized by several national organizations. He received awards from the National Gay and Lesbian Task Force, the Gay and Lesbian Press Association, Lambda Legal Defense and Education Fund and the Rockefeller Foundation, among others. On December 1, 1993, he received the City of Los Angeles Lifetime Achievement Award. He also became a leading voice in gay and lesbian politics. Callen was a popular singer and composer, first with the a cappella group "The Flirtations," with whom he toured and recorded two hit albums, and then as a soloist, with his famous "Legacy" Album, which earned him many awards. He leaves behind such a legacy against AIDS and the fight for gay rights.