Stereoview with caption: "766. Waiting for a Shave." Backmark: "Photographed and Published by KILBURN BROTHERS, Littleton, N.H."

This stereoview has all kinds of content, in addition to the barber/haircut/shave theme:
Very nice details are visible: rifle, bottle, sleeping dog, posters, ...

One of the posters could be for Carleton, a photographer/daguerreotypist from Portland, Maine.

Handwritten on the back: "Gift of W S. Appleton 23 June 1923." Surely this is William Sumner Appleton, who amassed notable collections of coins and medals. American Journal of Numismatics, and Bulletin of the American Numismatic and Archaeological Society published an article, 'A Selection of Coins from the Cabinet of W.S. Appleton,' in July, 1870 (Volume 4, No. 1).