When you think of Stevie Wonder’s legendary career, what chart-toppers come to mind? “Superstition,” right? Maybe “I Wish”? Okay, but what about the start of his career, on the Motown of the ’60s? You may not know that Wonder had only one Hot 100 No. 1 in his first decade—as “Little” Stevie Wonder—and it was truly exceptional, as in bizarre: a semi-improvised live recording of a “12 Year-Old Genius” refusing to leave a Chicago stage and say goodnight. Here’s the story of “Fingertips, Part 2,” and the years that launched a true pop icon. Wonder’s imperial run of classic, chart-topping, Grammy-dominating ’70s albums had their seeds in the joyous virtuosity, and fierce independence, on display in his very first hit.Email: hitparade@slate.com  Learn more about your ad choices. Visit megaphone.fm/adchoices