Monk abides. That's Monk, as in Thelonious Sphere Monk. If the name rings with a slightly off-kilter resonance, at once elegant and a touch uncanny, it's only appropriate. The jazz composer and pianist, who would have turned ninety this October, was a singular brand of genius, an idiosyncratic marvel, and a pivotal figure in American music. Once you'd heard him, you could never forget him.