Hi, drumvik, I would recommend that anyone take 5-years and study Wilber's oeuvre. I did, I read his whole works over a decade and would recommend anyone interested head over to Frank Visser's site Integral World and spent an equal amount of time applying critical thinking to what you're reading--don't believe all the hype.
BTW: zackery, above puts SDI to one of its worst abuses: pigeonholing​ people​l SDI is a decent tool to have in the box but if one doesn't know how to use a hammer properly....
And also, Wilber could be flat out wrong in his spiritual cosmology. Tread carefully:)