Tom Magliozzi, one of public radio's most popular personalities, died on Monday November 3rd of complications from Alzheimer's disease. He was 77 years old. Tom and his brother, Ray, became famous as "Click and Clack the Tappet Brothers" on the weekly NPR show Car Talk. They bantered, told jokes, laughed and sometimes even gave pretty good advice to listeners who called in with their car troubles. If there was one thing that defined Tom Magliozzi, it was his laugh. It was loud, it was constant, and it was infectious. The Magliozzi brothers grew up in a tough neighborhood of East Cambridge, Mass., in a close-knit Italian family. Tom was 12 years older than Ray. They both graduated from MIT. After getting out of college, Tom went to work as an engineer. One day he had a kind of epiphany; He was on his way to work when he had a near-fatal accident with a tractor-trailer. He pulled off the road and decided to do something different with his life. "I quit my job," he said, became a bum and spent two years sitting in Harvard Square drinking coffee and working part time as a consultant and college professor. Eventually he got a doctoral degree in marketing. Tom and Ray Magliozzi opened a do-it-yourself auto repair shop in the early '70s. They called it Hackers Haven, and later they opened a more traditional car repair shop called the Good News Garage. They got into radio by accident when someone from the local public radio station, WBUR, was putting together a panel of car mechanics for a talk show. They called Ray, and Ray thought it was a dumb idea, so he said, 'I'll send my brother' and Tom thought, 'Great, I'll get out of breaking my knuckles for a couple of hours.' He went over and was the only mechanic who showed up. The station liked what Tom did and asked him to come back the next week. This time he brought Ray. The rest, as they say, is history. In 1987 Car Talk went national on NPR. (R) Tom & Ray Magliozzi (L)