"Numbers" is the ninth studio album and first concept album by singer-songwriter Cat Stevens, released in November 1975. The album is subtitled "A Pythagorean Theory Tale" and is set on a fictional planet called Polygor. The story involves a castle with a "number machine" that dispenses the numbers 1 through 9 (excluding 0) to the universe. The planet's inhabitants, the Polygons, follow a routine existence until the arrival of Jzero, a mysterious figure who disrupts their world with simple truths.
The album was accompanied by a booklet featuring excerpts from a planned book and illustrations by Stevens. Musically, Numbers was a departure from Stevens' previous works, lacking the catchy pop songs his fans had come to expect. This confused both fans and critics, and while the album eventually achieved gold status, it sold far less than his prior albums and was deemed a critical failure. Stevens was reportedly frustrated with the pressures of fame and distanced himself from promoting the album.
Despite the album's poor reception, Stevens continued his career, releasing the successful Izitso in 1977, which marked his return to pop music. However, by the early 1980s, Stevens embraced Islam, changed his name to Yusuf Islam, and left the music industry to focus on his faith and humanitarian work. Numbers was later re-released in a limited edition box set in 1994, making it a rare collector's item.