If you are interested in exploring Abelard's contributions to logic and philosophy, the best place to start is The Philosophy of Peter Abelard by John Marenbon. For background on the intellectual climate of the time, I highly recommend a book that is old but still vital: The Renaissance of the Twelfth Century by C.H. Haskins. Johan Huizinga has an interesting essay on Abelard in Men and Ideas. Abelard's Ethical Writings are available in a fairly recent translation by Paul Vincent Spade, as are some of Abelard's writings on the problem of universals.