Sailing to Byzantium: an architectural companion - OsbertLancaster

This delightful book was one of a pair of John Murray-published books (this one 1969 - the other 1899) on the architectural history of the Byzantine Empire that I picked up at Nicholas Potter books in Santa Fe a couple of weeks ago.  It is a small architerctural companion by Lancaster, a noted British cartoonist, explaining Byzantine architecture to travelers who might encounter isolated examples throughout the Eastern Mediterranean.  It begins literally with the Christians' move aboveground into their first churches following the Emperor Constantine's adoption of the religiion in the fourth century, and then explains the architectural differences between the churches that occurred as the Eastern and Western churches diverged over the centuries.  I liked it very much.