If you're interested in salsa, one of the best books on the subject, by the Venezuelan César Rondón, happens to be online through the BU library.
Before there was salsa...
The early 1960's charanga boom:
Eddie Palmieri and La Perfecta's two-trombone sound (borrowed from Mon Rivera, a plena singer in Puerto Rico) was a revelation in 1962, and would provide the perfect amount of New York grit for what would become salsa.
From Lo mato: "Calle luna, calle sol" by Willie Colón with Hector Lavoe (Rondón 68). Lavoe sings:
"Put your hand in your pocket, pull out your knife and open it. Listen to me, in this neighborhood they've killed a lot of tough guys. In these tough streets, you can't relax. Be careful with your words - you're not worth a kilo."
Their albim "Asalto Navideño" - a pun mixing their usual street tough image with traditional Purto Rican Christmas caroling (sort of) - incorporated the cuatro from música jíbara.
It also contains the first of many experiments by Colón with non-Cuban music - not only música jíbara, but Panamanian murga. Colón's later "El gran varón" deals with homosexuality and AIDS
Lavoe, who was born in Puerto Rico and came to NY as a young man, was popular in part because of how much his voice was heard as reminiscent of música jíbrar, even though he was no traditionalist. He was wont to insert an improvised "Le lo lai" from música jíbara whenever the mood struck, even in a non-Puerto Rican song like the apocalyptic masterpiece "Todo tiene su final" ("Everything Ends"). New York Puerto Ricans identified very strongly with him, and songs like "Mi Gente/My People" (here sung with the Fania All-Stars in Zaire - Cuban music and salsa have been popular in West Africa since the "rhumba" days - in 1975, for the Ali-Foreman "Rumble in the Jungle"). He also sang religious themes, such as the santería-influenced "Aguanile."His most famous song was "El cantante," about a famous singer whom despite his fame and acclaim, has just as much pain as anyone else, which became sadly auto-biographical as Lavoe's inner demons took over his life through the 1980s and 1990s
Salsa was, among the things, a nationalist movement, as illustrated in the Fania film, Our Latin Thing (Cosa nuestra)
People have been, and still are playing rumba in the parks of New York.
Bonus: The Young Lords
The Young Lords, whose 13 Point Plan included rights for US Puerto Ricans, the independence of the island of Puerto Rico, women's liberation, and solidarity with the Vietnamese people, began in Chicago in 1967, spread to New York (and beyond) in 1969, and was influential until the mid 1970s.