According to his doting mother, little Isaac Mizrahi delighted in the daisies on a pair of her mules when he was four. A few years later, he regularly pinched cash from his parents' dressing table while they slept and used it to buy fabric at a Brooklyn dry-goods emporium. At 17 he whipped up a special purple suit to wear on his first trip to Paris. No surprise, then, that young Isaac became a successful fashion designer whose business straddles youthful downtown chic and conservative uptown department stores.
Now 33, Mizrahi is the subject of Unzipped, one of the smartest and...