After the stress of promoting Radiohead's acclaimed 1997 album "OK Computer", songwriter Thom Yorke wanted to diverge from rock music. Drawing influence from electronic music, ambient music, krautrock, jazz, and 20th-century classical music, Radiohead used instruments such as modular synthesisers, ondes Martenot, brass and strings. They processed guitar sounds, incorporated samples and loops, and manipulated their recordings with software such as Pro Tools and Cubase. Yorke wrote many lyrics by cutting up words and phrases and assembling them at random. Radiohead considered releasing the material as a double album, but decided it was too dense; a second album of material from the sessions, "Amnesiac", was released the following year.