What books should teachers of composition read? 

Here's a working list (i.e. under construction), in no particular order, with links to tables of contents:

Ritter, Kelly, and Paul K. Matsuda, eds. Exploring Composition Studies: Sites, Issues, and Perspectives. Logan, Utah: Utah State University Press, 2012. Print. (On Amazon)

Harris, Joseph. A Teaching Subject: Composition Since 1966 New Ed. Logan, Utah: Utah State University Press, 2012. Print. (On Amazon) 

Miller, Susan. The Norton Book of Composition Studies. New York: W.W. Norton & Co, 2009. Print. (On Amazon)

Tate, Gary, Amy Rupiper, and Kurt Schick. A Guide to Composition Pedagogies. New York: Oxford University Press, 2001. Print. (On Amazon) 

Villanueva, Victor, and Kristin L. Arola, eds. Cross-talk in Comp Theory: A Reader. 3rd ed. Urbana, Ill: National Council of Teachers of English, 2011. Print. (On NCTE)

Ede, Lisa S. On Writing Research: The Braddock Essays, 1975-1998. Boston: Bedford/St. Martin's, 1999. Print. (On NCTE) 

Roen, Duane H., et al., eds. Strategies for Teaching First-Year Composition. Urbana, Ill: National Council of Teachers of English, 2002. Print. (On NCTE) 

Johnson, T R., ed. Teaching Composition: Background Readings. New York, NY: Bedford/St. Martins, 2008. Print. (On B/SM) 

Bloom, Lynn Z, Donald A. Daiker, and Edward M. White, eds. Composition in the Twenty-First Century: Crisis and Change. Carbondale: Southern Illinois University Press, 1997. Print.  (On Amazon)

White, Edward M. Assigning, Responding, Evaluating: A Writing Teacher's Guide 4th ed. Boston, MA: Bedford/St. Martin's Press, 2007. Print. (On B/SM)