Adventures in Unhistory: Conjectures on the Factual Foundations of Several Ancient Legends - Avram Davidson, George Barr, Peter S. Beagle
The style of these essays is highly eccentric: rambling and jokey, with some sentences so long you have to pay close attention to understand them. But some of the passages struck me as quite good. More important, though, is that (as it seems to me) the contents, analyses of the origins of some legends, are well-considered and thoroughly researched. I haven't found anything (unintentionally) ridiculous in these essays. In particular, the one about Prester John was really fascinating.