As a reference librarian, I'm often asked to recommend the quintessential book on a topic I don't know much about, a book that gives the general reader the broad outlines of a field in a compact, accessible format. Somewhere between a Wikipedia article and a shelf full of specialized tomes is the elusive "just right" kind of book.
Oxford University Press identified this need and launched a wonderful series called Very Short Introductions (VSI). Andrea Keegan, the series editor, told The Bookseller: "The books are not primers or surveys, but sophisticated 'takes' on a topic, and we allow the authors to express a point of view, while giving readers a really good way into a subject they may never have encountered before." Noted authorities in each field are commissioned to write an overview of no more than 200 pages.