The Modern Epidemiologist's Library
We live in a time when many reference books are no longer needed, mainly due to the Internet (who even owns a volume of Encyclopedias anymore, or for that matter, consults them). With most information a click away on websites like Wikipedia or a quick Internet search, buying and keeping heavy volumes may be a thing of the past for modern day students. Certainly I don't advocate doing away with hardcopy books (read Fahrenheit 451 if you doubt this) but I do question the mass production and distribution of reference material, especially didactic tomes.
Furthermore I'm also an advocate of "tiny living," almost to the point of being nomadic, able to pick up and relocate in a few boxes. Therefore, if I'm buying a book, it needs to be something that 1) I'll refer to time and again, and 2) not readily available / may not be readily available on the Internet. What I present here is my experience building an Epidemiologist's library, a question that I'm often asked as a teacher. These are the core "desert island" books that in my opinion are necessary for students of the profession.
And that's it for general reference. The entire field in four hardcopies (actually three seeing how you probably won't need to hang on to the Intro text). Again, I'm not trying to dissuade anyone from additional or supplemental books, but for me, this is what works, and I'm willing to bet for you too. I do have additional books, but they are electronic copies (PDFs) that I consult only rarely. I'm sure this list will generate disagreement; I'd love to hear what works for you.
For those that specialize in an area, I can see adding an additional book to the library. For me, as an infectious disease epidemiologist, I wanted to supplement this list, but without buying a host of books on immunology, disease pathology, outbreak investigation, disease modeling, and specific disease epidemiology (as I did when I was a student). Although pricey, Nelson's Infectious Disease Epidemiology is an absolute must and the bible of the field. This is probably the book I turn to most often these days (especially with the recent measle's outbreak).
Lastly, here are a few of my favorite websites that are particularly useful for statistical theory and programming reference. Hopefully you'll find them useful too: