Pork Pie brought together Dutch keyboard player Jasper van't Hof, American saxophonist Charlie Mariano and Belgian guitarist Philip Catherine. After Transitory, the group recorded The Door Is Open at Morgan Studio in Brussels between 29 July and 2 August 1975, with Danish bassist Bo Stief and English drummer John Marshall, then with Soft Machine. MPS released it in 1976.

The writing is shared: Mariano's pieces include Zana and Avoid The Year Of The Monkey, van't Hof contributed the title track, and Catherine the opener Devil Toes. Van't Hof plays electric and grand piano and a prepared organ, Catherine moves between electric and acoustic guitar and banjo. Mariano's interest in South Indian music shows in Telisi Rama, a composition by Tyagaraja on which he plays the nadaswaram. The result is open, often lyrical jazz-rock with room for long solos.

Japanese CD reissue by Belle Antique in a paper-sleeve mini LP replica with obi and Japanese insert, SHM-CD, remastered, limited edition.