When does Consider Phlebas return?

Consider Phlebas is the first in a series of novels about an interstellar society called the Culture. The Culture and the Idiran Empire are at war in a galaxy-spanning conflict. Its protagonist Bora Horza Gobuchul is an enemy of the Culture and is a shape-changing mercenary. The novel takes its title from a line in T. S. Eliot's poem The Waste Land.