Junius B. Smith & J.U. Giesy 
The Opposing Venus: The Complete Cabalistic Cases of Semi Dual, the Occult Detector [EPUB ebook] 

Semi Dual returns in another suspenseful mystery which only his occult skills can resolve. Dorien, a wealthy man about town, is shot and wounded in his apartment in the course of what Inspector Johnson suspects is an extortion attempt. But Dorien won’t talk, leading the Inspector to call on Glace & Bryce—private investigators—and their strange partner, Semi Dual, the recluse and astrologist who uses his occult powers to straighten out the tangles of human affairs.