Dr. G. S. P. Freeman-Grenville was the consultant for Burke's Royal Families of the World, & his major work was the Chronology of World History. This specially commissioned Book of the Kings & Queens & Britain, a magisterial & entertainingly written overview of British monarchs from Cerdic, First King of Wessex, to George VI, is an invaluable guide to the regal chronology of Britain, & contains many insights into the foibles of one of the world's most interesting & resilient constitutional monarchies -- through the vagaries of war, pestilence, regicide, civil wars & marriage. Includes maps & genealogical charts.
A good introduction and overview of the history of the monarchy in England, with a little additional on monarchs in Wales, Scotland, and Ireland. A good basic resource.
The kings and queens of Britain range from dreadfully boring to unrealistically interesting. This will also probably be on my currently-reading list to infinity: I read it before going to bed because, in the worst cases, it dulls my mind and hurts my eyes, and in the best, I can't put it down (and it still puts me to sleep). But in any case, it'll be awhile.