an integrated introduction to the ideas, theories, principles and methods of epidemiology
Raj S. Bhopal. Oxford University Press 2002 (1st edition), 2008 (2nd edition)
Full PDF of the 2002 edition (note: loads slowly!) (link)
This text is one of the most conceptual and thoughtful introductions to epidemiology, and therefore helpful in developing a broader perspective and deeper understanding of fundamental epidemiologic concepts. Raj Bhopal is also a leading thinker in the field of health equity, and equity issues receive appropriate attention in the textbook.