Chad Calhoun was a house name used for books 4 through 12 of the Agent Brad Spear series of westerns published by Dell in the early eighties. A search of copyright claims has determined the authors of all the Calhoun books but one. The author of 'The Frisco Lady' is unknown at present. The copyright claimant is Banbury Books, Inc., which isn't very helpful. 'The Frisco Lady' can be found credited to Chet Cunningham on many seller's sites, but the Calhoun name is definitely on the cover of the Dell paperback.