The treatment of a landscape painting long accepted but recently questioned as being a painting by Cézanne is described. An X-radiograph made at the Swiss Institute for Art Research revealed what appeared to be a still-life painting on the reverse of the double-lined original canvas. At the Solomon R. Guggenheim Museum, the landscape was cleaned. Cleaning revealed insufficient new information to confirm the attribution to Cézanne. After serious consideration, a decision was made to remove two linings to reveal the image on the reverse. Four small oil sketches were uncovered. The double-sided painting was then re-stretched onto a newly designed double-sided stretcher.