The artless, absorbing biography of a diminutive (5'4Â«"") Jewish strongman. Joseph L. (Yosselle Leib) Greenstein was born in 1893, the son of a desperately poor rabbi in Suvalk, Poland. He was a premature baby, a sickly asthmatic child, and a unanimous candidate for an early grave, when a wrestler in a traveling circus took him on as his valet and disciple, and singiehandedly transformed him into a budding Samson. (Later on, in fact, Greenstein let his hair grow and pulled trucks with it.) In 1911 he emigrated to the States, and embarked on an adventurous career that found him learning jujitsu in Yokohama, fighting Klansmen in Houston, and, finally, going on the vaudeville circuit, astounding audiences as he tore horseshoes apart, bit through chains, and supported a ten-man Dixieland band--in a pickup truck-while lying on a bed of nails. By the 1930s public interest in such grisly heroics began to fade, and Greenstein moved on, to create and promote his line of Mighty Atom Health Products. Eventually he passed into almost total obscurity when Spielman ran into him at a martial arts show in Madison Square Garden and discovered not just a fascinating bit of show business history, but a splendid, warm, intelligent mensch.