Upton Sinclair Signed 8x10 Photo Writing 1930s

Upton Sinclair, signed 10 by 8 inch photo of Sinclair writing, probably from the 1930s, in very good condition as there are glued pieces of paper on the back from the photo once being included in a scrap book or such.  The photo of the well known author and socialist politician who ran for Governor of California as a Democrat in 1934 comes from a Southern California collector who amassed well over 5,000 autographs in the 1970s.