If you’re in the mood for a little self-improvement at the start of the year, you’ll have no trouble finding guides; there are at least 45,000 self-help books currently in print. They run the gamut: the self-made man, mind-cures, chicken soup, subliminal messages and Zen meditation. They’re published in dozens of languages, but self-help books are predominately an American phenomenon. To explain why, we turn to Laura Vanderkam, author of “The Paperback Quest for Joy”.