Thick as a Brick is the fifth studio album by the English band Jethro Tull, released in 1972. The album is notable for only including one song, which spans the entire album. Thick as a Brick was deliberately crafted in the style of a concept album (and as a "bombastic" and "over the top" parody). The original packaging, designed like a newspaper, claims the album to be a musical adaptation of an epic poem by a (fictional) 8-year-old boy, though the lyrics were actually written by the band's frontman, Ian Anderson. The album was a commercial success and topped the US charts.
Thick as a Brick was considered by some to be Jethro Tull's first progressive rock offering, coming four years after the release of their first album (1968). The epic album is notable for its many musical themes, time signature changes and tempo shifts — all of which were features of the progressive rock scene. In addition, the instrumentation includes harpsichord, xylophone, timpani, violin, lute, trumpet, saxophone, and a string section—all uncommon in the band's earlier blues-inspired rock.
Band frontman Ian Anderson was surprised by the critical reaction to their previous album, Aqualung (1971), as a "concept album", a label he firmly rejects to this day. In an interview on In the Studio with Redbeard (which spotlighted Thick as a Brick), Anderson's response was to "come up with something that really is the mother of all concept albums". Taking Monty Python as an influence, he began to write a piece that would combine complex music with a sense of humour, with the idea it would poke light-hearted fun at the band, the audience, and the music critics. Anderson has also stated that "the album was a spoof to the albums of Yes and Emerson, Lake & Palmer, much like what the movie Airplane! had been to Airport" and later stated that is was a "bit of a satire about the whole concept of grand rock-based concept albums." Although Anderson wrote all the music and lyrics, he decided to co-credit the writing to a fictional schoolboy named Gerald Bostock. The humour was subtle enough that some fans believed that Bostock was real. Reviewing the 40th anniversary reissue, Noel Murray suggested that many listeners of the original album "missed the joke".