Here's something very useful to check out. With eScholarship Editions, the University of California Press has digitized all the books it has published in living memory, and about one-third of those have been made available to the reading public, free of charge, in their searchable and printable entirety. Searching for the keyword "History" finds 518 books available to the likes of us, free. These include all kinds of recent and important works, including, for example, David B. Edwards, Before Taliban: Genealogies of the Afghan Jihad (2002); Antoinette Burton, At the Heart of the Empire: Indians and the Colonial Encounter in Late-Victorian Britain (2000); and Peter Earle, The Making of the English Middle Class: Business, Society and Family Life in London 1660-1730 (1989). There are even numerous volumes on the history of science, if you really must. Having these texts available means that students can get their mitts on them when they need them, and instructors can assign them to an unlimited number of students. And did we say they were free? Check out the whole list at http://content.cdlib.org/escholarship/