claim: A player-coach is unable to become a head coach.
evidence: The To the Stars trilogy is a series of science fiction novels by Harry Harrison , first published in 1980 -LRB- Homeworld -RRB- and 1981 -LRB- Wheelworld and Starworld -RRB- .. trilogy. trilogy. science fiction. science fiction. Harry Harrison. Harry Harrison ( writer ). The three books were re-published in an omnibus edition in 1991 .