YOU PROBABLY haven’t heard of him, but, among the insulated world of Philadelphia’s journalistic and political cognoscenti, there’s long been a very special celebrity, someone mayors and governors and editors and talking heads alike go out of their way not only to greet, but to befriend. He is perhaps the only Philadelphian beloved by both Democrats and Republicans, and by competing beat writers. He is not someone with a privileged position or a lot of power. He simply has a huge heart, a mischievous smile and an infectious way of looking at the world — and this makes people want him to like them. This week, the rest of the world will get to know him as the niche phenomenon of Zach Bissinger goes mass with the publication of his father’s book, Father’s Day: A Journey Into the Mind & Heart of My Extraordinary Son. Zach, the 28-year-old special-needs son of Philadelphia writer Buzz Bissinger, is my friend and employee: I hired him a year ago to work eight hours a week in our newsroom, delivering mail and stocking supplies. I’ve known his father nearly 20 years, and the competitive part of me has hated Buzz for his prodigious talent that long. Now he has captured Zach on the page and, in the process, written an important book. Because Zach truly is extraordinary. Buzz’s twins were born prematurely, and three minutes apart: Gerry, born first, thrived and is today a teacher and grad student; Zach was born with trace brain damage, but it soon became apparent that he was also a savant. He remembers strangers’ birthdays for decades. He can tell you precisely, and immediately, on what day of the week any date in history falls. He memorizes maps like a computer on legs. But that alone doesn’t capture how inspiring he can be. He is intensely social, and his daily all-caps emails to legions of Philadelphians are his way of seeking connection. I’m lucky to have been on his list: