The latest edition of Writer's Market is available in Beeghly Reference PN161 .W83.
This essential resource is an index of a literary agents, book publishers, consumer magazines (from many different subject areas), trade journals (also from many different subject areas), and more. Every year's edition includes an extensive front section full of advice on how to find work, manage your work, and promote your work.
The 2012 edition is currently available on Amazon for under $20. Awesome!!
*There is also a Poet's Market. If you're a poet, you should definitely purchase/use this instead of WM.
Literary Market Place is conveniently located right next to Writer's Market in Beeghly Reference PN161 .L5.
An incredibly throrough directory, LMP covers American and Canadian publishers, literary agents, manufacturers, and more.