Complete Encyclopedia Britannica, as well as Merriam-Webster's Collegiate Dictionary and Thesaurus, Britannica Student Encyclopedia and the Britannica Book of the Year. Also includes a directory of more than 300,000 websites vetted by Britannica editors.
Dictionary of the Middle Ages
by
Joseph R. Strayer (Editor)
important encyclopedia for medieval studies, which covers the period from 300 to 1500 AD/CE for the whole of Europe and parts of the Middle East and North Africa.
Bloomsbury Cultural History of the Western Empires -- on order.