The Chronicle of Higher Education, both in its blog and in print, frequently studies the fact that many PhDs never find a tenured position in academia. (The Chronicle is available online to subscribers and can be found in most academic libraries.) An article from November 2011 by A.W. June, entitled "More Universities Break the Taboo and Talk to Ph.D.'s About Jobs Outside Academe" (http://chronicle.com/article/More-Universities-Break-the/129647/), is an excellent survey of the current state of affairs. The article describes a web site called "The Versatile PhD”, which aims to offer "first-hand advice about nonacademic careers for humanities & social science PhDs." (http://versatilephd.com/)
The prudent recent PhD must consider that current market conditions or personal priorities may rule out a permanent academic career. Yet, as observed above for those with a BA degree in the Classics, the skills and abilities provided by such training have proved to be useful outside of academia in the fields listed above. The problem is really one of rhetoric, of learning to describe one's qualifications and experience in ways that emphasize the proper things. One also needs to deal with the prejudices on both sides, which hinder communication and understanding between trained academics and representatives of business and industry. The non-academic sector, for example, may stress cooperative work over independent research, will generally think in terms of more immediate deadlines, and will tend to emphasize production over credentials.
The best places to begin are by talking with a college or university career counselor and by browsing among the steady flow of books and articles that deal with career planning and career transition. A standard book, with a well-deserved popularity, is Richard Nelson Bolles, What Color Is Your Parachute 2012- A Practical Manual for Job-Hunters & Career Changers. (Ten Speed Press, updated annually).
Still of some use, though a bit out-of-date, is Elaine Showalter, The MLA Guide to the Job Search: : A Career Guide for PhDs and PhD Candidates in English and Foreign Languages (rev. ed., MLA, 1985). Chapter 4, by Howard Figler, is entitled "Succeeding in the Nonacademic Job Market" (pp.75-101). It discusses many career opportunities outside higher education for PhDs in the humanities and ends with a bibliography for further reading.