22. Paul Allen
$20.6 billion Self-made Score: * Source: microsoft, investments age: 64 residence: mercer island, wash. dropout, washington State
allen dropped out of washington state to work at aerospace company trw. he then moved to boston, where bill gates (no. 1), his former high school classmate at lakeside school, was attending harvard. the pair cofounded microsoft in 1975. allen left the software firm 8 years later after being diagnosed with hodgkin’s disease. he beat the disease and has gone on to pursue a range of interests and philanthropic causes, from satellites and brain science to artificial intelligence and sports. in august, his research vessel Petrel discovered the wreckage of the Uss Indianapolis in the philippine sea.