In the summer of 1971, cable executive Charles Dolan was aboard the Queen Elizabeth II on a family vacation, trying to save his money-losing company. Sterling Manhattan Cable was building the first urban underground cable system in the U.S., trenching wire past water mains, subway lines and gas pipes beneath New York. His idea, first called the Green Channel, was unedited Hollywood movies and live sports with no commercials for a flat monthly fee. Time Inc.’s board gave him a $150,000 development grant, the Sterling Cable Network name was dropped, and Home Box Office launched on November 8, 1972, not in Manhattan but on a system in Wilkes-Barre, Pennsylvania, with 365 subscribers. Night one was a New York Rangers and Vancouver Canucks game from Madison Square Garden followed by the Paul Newman film Sometimes a Great Notion.

In September 1975 HBO became the first channel in the world to transmit nationally by satellite, letting any cable operator with a dish carry it. To fight churn it launched Cinemax as a 24-hour sister channel in August 1980, and in 1991 became the first subscription service to multiplex, giving away extra feeds at no charge and later adding family, comedy and Latino channels. In the early 1980s it dropped exclusive studio deals because VHS rentals reached viewers first, then returned to multibillion-dollar exclusive deals with Warner Bros., TriStar and Columbia as Showtime competed, and the 1989 Time Warner merger locked in pay cable rights to Warner Bros. films. In 2015 its CEO defended weekly releases over binge drops.

• HBO launched a high-definition feed in 1999 but waited until early 2001, the third-season premiere of The Sopranos, to show a first-run original in HD.
• Its first video on demand service launched in South Carolina in 2001.
• Inside the NFL debuted on HBO in 1977, years before similar weekly shows on sports cable networks.
• The family multiplex channel limited its content to PG-13 and below to build trust with parents.
• The slogan “It’s not TV, it’s HBO” caught on in 1999.