Pink Floyd released Animals on January 21, 1977, and the timing was not incidental. Britain in 1976 was a country that felt like it was losing an argument with itself. Inflation had gutted household income. The government had gone cap in hand to the International Monetary Fund for a bailout, a humiliation that landed like a national gut-punch. Garbage piled up in the streets during labor strikes. And from the clubs of London and Manchester, a new generation of musicians was screaming that the whole edifice deserved to burn. Roger Waters was watching all of it, and he had things to say.

The album he built from that fury runs forty minutes across five tracks. It opens and closes with "Pigs on the Wing," a pair of short acoustic pieces that function as human parentheses around the carnage inside. Between them sit three extended compositions: "Dogs," a 17-minute co-write between Waters and David Gilmour that occupies most of side one; "Pigs (Three Different Ones)," an eleven-minute assault on the ruling class; and "Sheep," ten minutes of building dread that ends in a brief, doomed rebellion. The structure is borrowed from George Orwell's Animal Farm, with pigs representing the corrupt elite, dogs the ruthless corporate climbers, and sheep the passive, manipulated masses. Waters wasn't being subtle, and he wasn't trying to be. As he told Capital Radio in 1977, "It is a very violent album. They're quite violent songs, so I think that's why the music is a bit punchier."

The record was made at Britannia Row Studios in Islington, north London, a three-storey block of converted church halls that Pink Floyd had purchased in 1975 and spent most of that year turning into a recording space. It was engineered by Brian Humphries, who had worked with the band before, and self-produced by the group. Recording ran from April 1976 through early 1977. The studio was theirs, which meant they could take their time, and they did. But something else was happening in those sessions that the finished record can't quite hide. Keyboardist Richard Wright, dealing with a crumbling marriage and a severe case of writer's block, contributed so little that Animals became the first Pink Floyd album not to carry a composer's credit for him. Wright later told Nicholas Schaffner, author of Saucerful of Secrets, "That was the first one I didn't write anything for. And it was the first album, for me, where the group was losing its unity as well." He added, flatly: "It's not my favorite album of the Floyd."

Waters was closing himself off from the others, increasingly arriving at venues alone and departing the moment each show ended. Gilmour, for his part, was doing the heavy lifting musically. "Ninety percent of the song 'Dogs' was mine," Gilmour told Mojo in 2008. "That song was almost the whole of one side, so that's half of Animals." On "Pigs (Three Different Ones)," Gilmour ran his guitar through a talk box to produce a sound like a squealing pig, a piece of studio craft that sat perfectly inside Waters' allegorical scheme. The album also contained a pointed lyrical attack on Mary Whitehouse, the conservative moral crusader who had made herself a fixture of British public life. Waters named her directly. The band released no singles. The music was the argument, and it didn't need a radio-friendly door in.

The cover image tells its own story. Waters had cycled around south London and photographed Battersea Power Station, drawn to what he described as its "doomy, inhuman" quality. He conceived the idea of floating an inflatable pig between the four chimneys, a visual that would rhyme with the album's title and its recurring "Pigs on the Wing" motif. The band hired art group Hipgnosis for the shoot, scheduled for three days in early December 1976. On the second day, December 3rd, a 40-foot helium-filled pig named Algie broke free of its moorings. The marksman who had been hired to shoot it down if it escaped had not been booked for the second day. Algie rose into the flight path of planes landing at Heathrow, was spotted by airline pilots at 30,000 feet, and eventually came down on a farm in Kent, where it frightened a herd of cows. Flights were grounded. Police helicopters scrambled. Hipgnosis co-founder Aubrey Powell was arrested. The album cover the band actually used was a composite: the dramatic cloudy sky from day one, the pig from day three, when Algie had been retrieved, repaired, and hoisted again with two marksmen present.

Animals sold more than four million copies and reached the top ten on both sides of the Atlantic. The In the Flesh tour began in Dortmund on the same day the album was released, January 21, 1977, and ran through Europe, the UK, and two separate American legs. On tour, a replica of Algie floated above audiences each night, replaced during each performance by an explosive version. The shows were spectacular and increasingly tense. Waters' alienation from the crowds was deepening, and his frustration with the audiences on that tour would eventually seed the concept for The Wall. But that's where the story goes next. Animals is where it fractures. The album is a document of a band at the exact moment when the political fury in the music and the personal fury inside the room became the same thing, and the record sounds exactly like that: enormous, raw, and barely contained.