We would do a disservice if we did not mention stylebooks. Many writers and journalists live by them. A better way of saying it would be: Many publications insist you write as indicated in a particular stylebook. If we were purchasing them, we would get the paperback editions as most are updated frequently. The ones we feel are at the top include:
The Associated Press Stylebook by Associated Press
The Chicago Manual of Style by University of Chicago Press Staff or http://www.chicagomanualofstyle.org/
The New York Times Manual of Style and Usage: The Official Style Guide Used by the Writers and Editors of the World’s Most Authoritative Newspaper, by Allan M. Siegan and William G. Connolly.