As the years spiral since its release, the Beach Boys’ Pet Sounds continues to be fascinating from two separate, though not unrelated, perspectives: musical and historical. The album is both an abrupt break from the Beach Boys’ past repertoire, which for the previous five years had been dominated by upbeat songs about early-‘60s Southern California teen life (surfing, girls, cars), and Brian Wilson’s successful bid for pop immortality. Some believe it represents rock’s first example of the thematically unified “concept album,” as its songs sketch out an anxiety-ridden romance from the breezy “Wouldn’t It Be Nice” to the emotionally bereft “Caroline No.” Others continue to admire its lush instrumental arrangements and meticulous attention to detail that came at a steep personal cost to Wilson, Pet Sounds’ principal architect.

With Wilson bringing the album’s 50th-anniversary tour to Houston Friday, Pet Sounds has been imitated, studied, written about and reinterpreted so much that today it can almost be considered a living organism as much as a piece of music. It’s one of the relatively rare albums from a half-century ago that both stand for their era in music history and continue speaking to subsequent generations of musicians. The reason is simple: Whenever talk turns to music, Pet Sounds has rarely left the conversation.

Summer 1965-April 1966: Inspired by Phil Spector and the Beatles’ Rubber Soul, the Beach Boys record Pet Sounds throughout ten sometimes difficult months; the record is later estimated to cost their label, Capitol Records, $70,000. Although they do sing, beautifully, the other band members are largely pushed aside in favor of a fleet of session musicians, some of whom later became known as the famous “Wrecking Crew.”

December 1965: After the Beach Boys perform on the hit TV show Shindig!, Brian Wilson (then 22) has an epiphany on a flight to Houston and decides to cease touring in favor of the composing/arranging life.

March 1966: Wilson releases “Caroline No” as a solo single, the first Beach Boy to do so. The song later appears on Pet Sounds.

May 16, 1966: Capitol releases Pet Sounds, on the same day Columbia issues Bob Dylan’s Blonde on Blonde.

July 1966: Hoping to mitigate Pet Sounds’ underwhelming sales, Capitol releases the Best of the Beach Boys compilation.

1967: Pet Sounds proved a much bigger hit in the UK, inspiring British musicians like Eric Clapton, Spencer Davis and, directly, The Beatles’ Sgt. Pepper’s Lonely Hearts Club Band. According to albumlinernotes.com, in a 1990 conversation with interviewer David Leaf, Paul McCartney says, “I have a two-hour drive normally to London; I played Sgt. Pepper on the way in, and then Pet Sounds on the way out, and both of them have more than held up.”

June 1972: Re-reviewing Pet Sounds in Rolling Stone, Stephen Davis says, "This trenchant cycle of love songs has the emotional impact of a shatteringly evocative novel, and by God if this little record didn't change [not] only the course of popular music, but the course of a few lives in the bargain." Later, theorizing about the public's heretofore general indifference toward the album, he adds, "Nobody was prepared for anything so soulful, so lovely, something one had to think about so much."

November 4, 1976: Brian is interviewed by Rolling Stone’s David Felton. Although the two discuss post-Pet Sounds No. 1 single “Good Vibrations” at some length, the album comes up only once, when Wilson explains what he calls “the Phil Spector approach”: “utilizing many instruments to combine for a single form or a single sound. Like combining clarinets, trombones and saxophones to give you a certain sound, rather than hearing that arrangement as ‘oh, those are piccolos, oh, those are trombones.’

1995: Contributors of UK music magazine MOJO vote Pet Sounds its Greatest Album of All Time.

1996: According to Rolling Stone’s Encyclopedia of Rock and Roll, Pet Sounds is finally certified Gold, signifying sales of more than 500,000 units.

2005: Quintessence/Universe publishes 1001 Albums You Must Hear Before You Die. Reviewer Seth Jacobson says of Pet Sounds, “Gone were the one-dimensional sun n’ surf anthems; in their stead, a more complex sound emerged, joyous but tinged with deeper, troubled emotions.”

2008: Hyperliterate Austin indie-rockers Okkervil River appropriate Pet Sounds’ “Sloop John B” for “John Allyn Smith Sails,”a track on their album The Stage Names.

2014: The film Love and Mercy, starring Paul Dano as a younger Brian Wilson and John Cusack as an older version, features the creation of Pet Sounds as a major plot point.

April 2017: Showtime airs the BBC-produced documentary Beach Boys: Making Pet Sounds, which the L.A. Times calls “an intermittently illuminating, rarely dull and, if only for the music, often moving hour.”

May 2017: Brian Wilson brings the Pet Sounds 50th-anniversary tour to Revention Music Center May 12.