Many require them. There is a second advantage to writing book proposal. Writer's Guide to Book Editors, Publishers, and Literary Agents, 2001-2002. And we just as frequently point to this book as the place to start. Weighing in at about 1,000 pages, it lists countless editors at over 500 publisher houses.
Extensive coverage is given to the world of literary agents.
Wiley 1993 Holm, Kirsten, ed. Who Buy What You Write. Coverage extends to book producers, syndicates, and greeting-card publishers, and some of the literary agents. Improved graphics show new listings, plus this book contains a chart presenting the owners and the imprints of the major book publishers. The Directory of the American Book Publishing Industry With Industry Yellow Pages.