The Normal Heart is a largely autobiographical play by Larry Kramer. It focuses on the rise of the HIV/AIDS epidemic in New York City between 1981 and 1984, as seen through the eyes of writer/activist Ned Weeks, the gay founder of a prominent HIV advocacy group. The play's title comes from W. H. Auden's poem, "September 1, 1939".

After a successful 1985 off-Broadway production at The Public Theater, the play was staged in Los Angeles and London. It was revived off-Broadway in 2004, and finally made its Broadway debut in 2011. The play was first published by Plume in the US, and by Drama Editor Nick Hern for Methuen in the UK to coincide with the 1986 British première at London's Royal Court Theatre. He then reissued it in his own imprint Nick Hern Books in 2011 when first staged on Broadway, and again in a tie-in edition alongside the National Theatre revival in 2021.

During the early 1980s, Jewish-American writer and gay activist Ned Weeks struggles to pull together an organization focused on raising awareness about the fact that an unidentified disease is killing off a specific group of people: gay men, largely in New York City. Dr. Emma Brookner, a physician and survivor of polio (as a consequence of which she is using a wheelchair), has the most experience with this strange new disease. She bemoans the lack of medical knowledge about the illness, and encourages gay men to practice abstinence for their own safety, since it is still unknown how the disease is spread. Ned, a patient and friend of Brookner's, calls upon his lawyer brother, Ben, to help fund his crisis organization; however, Ben's attitude toward his brother is one of merely passive support, which ultimately exposes his homophobia. For the first time in his life, meanwhile, Ned falls in love, beginning a relationship with New York Times writer Felix Turner.

The increasing death toll raises the unknown illness, by this time correctly believed to be caused by a virus, to the status of an epidemic, though the press remains largely silent on the issue. A sense of urgency guides Ned, who realizes that Ben is more interested in buying a two-million-dollar house than in backing Ned's activism. Ned explosively breaks off ties with his brother, not wanting further interaction until Ben can fully accept Ned's homosexuality. Ned next looks to Mayor Ed Koch's administration for help in financing research about the epidemic, which has now killed hundreds of gay men, including some of Ned's personal friends.

Ned's organization elects as its president Bruce Niles, who is described as the "good cop" of gay activism in implicit comparison to Ned: while Bruce is cautious, polite, deferential, and closeted, Ned is vociferous, confrontational, incendiary, openly gay, and supportive only of direct action. Tensions between the two are clear, though they must work together to effectively promote their organization. Felix, meanwhile, reveals to Ned his belief that he is now infected with the mysterious virus.

Although he continues to try to strengthen interactions with the mayor, Ned ruins his chances when his relentless and fiery personality appalls a representative sent by the mayor. Dr. Brookner gradually takes on the role of activist herself, and notes the epidemic's appearance in other countries and among heterosexuals. Although she desperately seeks government funding for further research, her request is denied; the rejection prompts her to unleash a passionate tirade against those who allow the persistence of an epidemic that is taking the lives of homosexuals, who are already marginalized by the government. In the meantime, Ned's conflict with Bruce comes to a head, and their organization's board of directors ultimately expels Ned from the group, believing his unstable vehemence to be a threat to the group's attempts to engage in calmer diplomacy.

As Felix's condition worsens, he visits Ben in order to make his will, and in the hope of effecting a reconciliation between Ben and his brother. All of them, along with Emma, meet at Felix's deathbed. Emma unofficially weds Felix and Ned, and Felix dies immediately after. Ned blames himself for his lover's death, lamenting that he did not fight hard enough to make his voice heard. The play ends with Ned and Ben embracing. As the stage fades to black, the rate of mortality from HIV/AIDS is shown to be continuing to increase.

After most performances of the 2011 revival of The Normal Heart, Kramer personally passed out a dramaturgical flyer detailing some of the real stories behind the play's characters. Kramer wrote that the character "Bruce" was based on Paul Popham, the president of the GMHC from 1981 until 1985; "Tommy" was based on Rodger McFarlane, who was executive director of GMHC and a founding member of ACT UP and Broadway Cares; and "Emma" was modeled after Dr. Linda Laubenstein, who treated some of the first New York cases of what later became known as AIDS. Like "Ned," Kramer himself helped to found several AIDS-activism groups, including Gay Men's Health Crisis (GMHC) and AIDS Coalition to Unleash Power (ACT UP), and indeed experienced personal conflict with his lawyer brother, Arthur.^{[citation needed]}