If you are looking for more general writing style guides, then go to General Writing Style Guides.

• Business English: A Complete Guide to Developing an Effective Business Writing Style (1993, 2nd edition), by Andrea B. Geffner. New York: Barrons Educational Series.
• The Business Student Writer's Manual and Guide to the Internet (1998), by Thomas P. Bergman, Stephen M. Garrison, and Gregory M. Scott. New York: Prentice Hall College Division.
• The Complete Idiot's Guide to Terrific Business Writing (1996), by Marcia Layton. New York: Macmillan.
• Dynamic Cover Letters (1995, 2nd edition), by Katharine Hansen and Randall S. Hansen. Berkeley, CA: Ten Speed Press.
• How to Create High Impact Business Reports (1996), by Joyce Kupsh. Lincolnwood, IL: NTC Publishing Group
• How to Write First-Class Business Correspondence (1995), by L.S. Baugh, M. Fyar, and D.A. Thomas. Lincolnwood, IL: NTC Publishing Group
• Manipulative Memos: Control Your Career Through the Medium of the Memo (1994) by Arthur D. Rosenberg and Ellen Fuchs Thorn. Berkeley, CA: Ten Speed Press.
• A Short Guide to Business Writing (1995), by Harrry J. Bruce, Russel K. Hirst, and Michael L. Keene. Englewood Cliffs, NJ: Prentice Hall.
• Style Manual: A Complete Guide With Model Formats for Every Business Writing Occasion (1992), by Mary A. DeVries. Englewood Cliffs, NJ: Prentice Hall.
• Successful Business Writing: How to Write Effective Letters, Proposals, Resumes, Speeches (1985), by Lassor A. Blumenthal. Perigee.
• Writing that Works: How to Improve Your Memos, Letters, Reports, Speeches, Resumes, Plans, and Other Business Papers (1992, 2nd edition), by Kenneth Roman. New York: HarperPerennial.
• Write to the Point (1988), by R.T. Fruehling and N.B. Oldham. New York: McGraw-Hill.
• Write to the Point: Letters, Memos, and Reports that Get Results (1992), by N.B. Oldham and Rosemary T. Fruehling. New York: McGraw-Hill.
• Write to the Top: Writing for Corporate Success (1989), by Deborah Dumaine. New York: Random House.
• Writing That Works (1993), by Sharon L. Pywell. Irwin.
• Writing That Works: How to Improve Your Memos, Letters, Reports, Speeches, Resumes, Plans, and Other Business Papers (1995), by Joel Raphaelson and Kenneth Roman. Harper Paperbacks.