With her sleek bob haircut (usually with a flower or two placed just so), vintage dresses, strikingly beautiful looks, and artfully customized ukulele, Janet Klein might seem at first to be a simple novelty act, a Generation X hipster ironically recreating the subtly naughty look of a fin-de-siècle French postcard. Then she opens her mouth to sing. There's no Betty Boop hiccups or Mae West-style brassiness in her charmingly original voice. And when she starts to play the ukulele, it's clear that this oft-ridiculed cousin of the guitar is neither prop nor gimmick, but a delightful and underutilized musical instrument. Bearing an ever-expanding repertoire of, as she puts it, "obscure, lovely, and naughty songs from the '10s, '20s, and '30s," Janet Klein is a musical archeologist hiding in a Gibson girl's body. Raised in San Bernardino, CA, during the '70s, Klein's early musical education came from her father, Stephen Klein, a teacher and avant-garde animator whose taste ran primarily to Frank Zappa and classical. Even more importantly, Klein's grandparents regaled her with tales of New York in the '30s (where her grandfather, Marty Klein, had worked as a stage magician), instilling in the girl a lifelong fascination with pre-World War II American popular culture. By the time Klein moved to Los Angeles to start college in the early '80s, this had translated into an interest in both early jazz recordings and the graphic design styles of the era. Through the former, Klein discovered early female jazz singers like Lil Hardin Armstrong (Louis Armstrong's wife and early manager) and Blanche Calloway (sister of Cab). The latter hobby led Klein to start collecting sheet music from the 1800s to the jazz age, at first purely for the pictures and artwork, then increasingly out of...