I have been searching the internet to find out about the twin lens camera because I have been told for many years that my great-great uncle, Don Beidler, was the inventor of this set up. I was very excited to see your post and wondered if you could share your knowledge about it. Don had triplet nieces, one of them was my grandmother, that he photographed on a regular basis. What great subjects for a child portrait camera. I was told that the camera was in the Smithsonian and did not realize that there was more than one of them. I have read in an old newspaper clipping that A. J. Viken, a man highly skillful in the mechanical end of photography was employed by Mr. Beidler in his studio in the Lyon and Healy building in, I believe, Chicago. Mr. Beidler was born Aug. 8, 1885 in Mt. Pulaski, Illinois and died at the age of 58 on Oct. 21, 1943.