Songs in the Key of Z is a book and two compilation albums written and compiled by Irwin Chusid. The book and albums explore the field of what Chusid coined as "outsider music". Chusid defines outsider music as; "crackpot and visionary music, where all trails lead essentially one place: over the edge." Chusid's work has brought the music of several leading performers in the outsider genre to wider attention. These include Daniel Johnston, Joe Meek, Jandek and Wesley Willis. In addition, his CDs feature some recordings by artists who produced very little work but placed their recordings firmly in the outsider area. Notable amongst these are nursing home resident Jack Mudurian who sings snatches of several dozen songs in a garbled collection known as Downloading the Repertoire and the obscure and extreme scat singer Shooby Taylor AKA 'The Human Horn.'