If you have no previous readings on Tibetan Buddhism, I would suggest looking over Matthew Kapstein's The Tibetans. It is a relatively straightforward read and an excellent introduction to Tibetan culture. A more encyclopedic work that can be used for spot reading is Geoffrey Samuel's Civilized Shamans.
The course then is going to be about the 10-14th century of Tibetan Buddhism, and the one book we will be reading in detail is Ronald Davidson's: Tibetan Renaissance: Tantric Buddhism In The Rebirth Of Tibetan Culture by Ronald M. Davidson ; 596 pages, Columbia University Press (November 13, 2005); ISBN-10: 0231134711; ISBN-13: 978-0231134712 That is not an easy book, but it deals with the crux of the course and we will be reading just about all of it. So if you want a jump start on the course, that is the book to try to pre-digest.
Otherwise a useful book - especially its first half - to orient you to general issues of how Tibet became Buddhist, and Buddhism became Tibetan, is: Kapstein, Matthew (2000), The Tibetan Assimilation of Buddhism: Conversion, Contestation and Memory; Oxford: Oxford University Press.
And all of this is all about tantric Buddhism, for which the best thing written is: Davidson, Ronald (2002). Indian Esoteric Buddhism: A Social History of the Tantric Movement. New York: Columbia University Press. ISBN 0-231-12619-0. If you want to read more detail on the Indian background, this is the one to look at, though the Renaissance covers it in its essentials early on.
Finally, David Snellgrove's two volume Indo-Tibetan Buddhism, while now dated, gives a good general overview of Indian tantric Buddhism in volume one, and is a good complement to Davidson's more social and political focus, which assumes the more basic knowledge covered by Snellgrove; and volume two is a good overview of the historical events and religious issues of our time period in Tibet.