JOE VOGEL is the author of three books, including the forthcoming Man in the Music: The Creative Life and Work of Michael Jackson (Sterling 2011). He writes about popular music and culture for The Huffington Post and PopMatters.Michael Jackson recorded loads of impressive material that didn’t make it onto his regular studio albums. The reasons for leaving tracks off were various: sometimes there just wasn’t enough space, sometimes they didn’t fit with the album as a whole, and sometimes he wanted to continue working on them. Many of these songs, however, were just as good as what ultimately made the cut. Unfortunately, that meant dozens of incredible tracks have gone almost completely overlooked by the average music listener.