by Thomas Bullfinch
Until Edith Hamilton came along, Bullfinch's Mythology was pretty much the standard for non-scholars and "normal folk" to brush up on their mythology. What's often sold as Bullfinch's Mythology is actually three books collected into one volume: The Age of Fable—retellings of Greek and Roman myths; The Age of Chivalry—stories about King Arthur; and Legends of Charlemagne—tales of the fictional/historical Charlemagne and paladins. To make things a little more confusing, the texts are well out of copyright, so anyone with a printing press and some paper can publish and sell their own Bullfinch.
It's a pretty swell resource to have, though, despite its artificial, 1800's era "thee's" and "thou's" to make the stories sound old and dignified. I actually find it kind of charming in Bullfinch. If nothing else, it's a book worth having for the Arthurian stuff, and other Celtic/Welsh tales. And I've never found the Charlemagne stories anywhere else, and they're great. In any event, you can sometimes find copies at bookstores on the bargain tables. I think I got my hardback version at a Barnes & Noble for about six bucks. The handsome leather-bound volume pictured above is about $17 on Amazon. I may order one, myself.
Bullfinch's Mythology (leather-bound) on Amazon.com
Bullfinch's Greek and Roman Mythology (Dover thrift edition) on Amazon.com
Bullfinch's Mythology, kind of readable online at Bartleby.com