Try some of these subject headings to find books on communication topics:
Business communication
Communication
Communication and culture
Communication in politics
Communication--methodology
Communication--research
Communication--social aspects
Interpersonal communication
Nonverbal communication
Persuasive communication
Public speaking
Rhetoric
Dictionary of Media and Communication Studies
Ref P87.5 .W38 2003
Encyclopedia of Communication Theory
Ref P87.5 .E496 2009
Sourcebook on Rhetoric: Key Concepts in Contemporary Rhetorical Studies
PN172. J37 2001
Encyclopedia of Public Relations
Ref HD59.E48 2005