First published in 2006 by McClelland and Stewart, Book of Longing contains 167 previously unpublished poems and drawings, mostly written at a Zen monastery on Mount Baldy in California, where Cohen lived from 1994 to 1999, and in India, which he visited regularly during the late 1990s.

Many of these poems were first published at The Blackening Pages of The Leonard Cohen Files [1] website.

Song Cycle Based on the Poetry and Artwork of Leonard Cohen, in which he set 23 of the book's poems to music.

The work was co-commissioned by Luminato Festival under the artistic direction of Chris Lorway in Toronto Canada, Australia's 2008 Adelaide Festival under the artistic direction of Brett Sheehy, and Barbican Centre in London, and premiered at Luminato in 2007.

At the Barbican Centre in London in October 2007, Cohen joined Glass onstage for a pre-concert discussion.