Bagnall, Roger S. The Encyclopedia of Ancient History. Malden, MA: Wiley-Blackwell, 2012. MAIN Reference 930.03 E563. Major work in the field.
Black, John, Nigar Hashimzade, and Gareth D. Myles. A Dictionary of Economics. 4th ed. Oxford: Oxford University Press, 2012. Internet. Quick definitions of terms used in modern economics.
Cancik, Hubert, and Helmuth Schneider. Brill's New Pauly: Encyclopaedia of the Ancient World. Leiden: Brill, 2002- . MAIN Reference 903 N481X or Internet. The premier scholarly encyclopedia on the ancient world. Can be a little tricky to use for the uninitiated. Citations in the bibliography often given in abbreviated form; to get full information, click on "New Pauly," and find list of "bibliographic abbreviations." Or email me and I'll be glad to help.
Durlauf, Steven N., and Lawrence Blume. The New Palgrave Dictionary of Economics Online. 2nd ed. Basingstoke, Hampshire: Palgrave Macmillian, 2008- . Internet. This is really an encyclopedia, rather than a dictionary in the ordinary use of the term. It is, in fact, the major encyclopedia covering the field of economics. The only work on this list that is continuously updated.
Gagarin, Michael, and Elaine Fantham. The Oxford Encyclopedia of Ancient Greece and Rome. Oxford: Oxford University Press, 2010. Internet. Less detailed than the New Pauly; designed more for the general student.
Hornblower, Simon, and Antony Spawforth. The Oxford Classical Dictionary. 4th ed.. Oxford: Oxford University Press, 2012. MAIN Large Books 913.38 O98 2012 or Internet. Key work for classical studies.
Mokyr, Joel. The Oxford Encyclopedia of Economic History. Oxford: Oxford University Press, 2003. MAIN Reference 330.03 O98 or Internet. Major work, edited by Northwestern's own Joel Mokyr.
Grant, Michael. Atlas of Classical History. 5th ed. New York: Oxford University Press, 1994. MUDD LIBRARY Annex 3 911.3 G762a 1994.
Scarre, Christopher. The Penguin Historical Atlas of Ancient Rome. London: Penguin Books, 1995. MUDD LIBRARY Annex 3 911.37 S286p.
Talbert, Richard J. A., and Roger S. Bagnall. Barrington Atlas of the Greek and Roman World. Princeton, N.J.: Princeton University Press, 2000. MAIN Government Info (Atlas Case) 912.38 B276. CD-ROM index available. The premier atlas of the classical world.
I'm regularly available in the Philosophy Department's Brentano Library (Kresge 3520) from 12:00 - 1:00 on Mondays, and in the Classics Seminar Room (Kresge 4364) from 4:00 to 5:00 on Tuesdays. I'm also always happy to meet in my office in the library by appointment: just click on the link above.