Unpaginated HTML ebook; also available (minus artwork) as plain text (us-ascii); all versions available from Ebook #23657.
Produced from Astounding, September and October 1959.
The listings at the top of the edition give the author's name as "Gordon Randall Garrett (AKA Mark Phillips)"; however, the listing within the text credits Mark Phillips, & the book publication (as Brain Twister by Mark Phillips) identifies this as a collaboration between Randall Garrett & Laurence M. Janifer.
The HTML version includes interior artwork (credited to Freas, some legibly signed Kelly Freas) from the magazine serial, & the transcriber's note includes a reproduction of the September magazine cover (this was the cover story), credited to Freas & legibly signed "Kelly Freas".
