Based on a historical character, a Norwegian who came to 1850's California, a story about some of the earliest skis in the US. According to the author, ``Snowshoe Thompson'' used his skis to carry mail over the Sierra Nevada when the mountains were deep in snow. In Levinson's fictional story, Thompson manufactures his own skis after his young friend Danny learns that the mail service has stopped until spring; Danny is distressed because he was counting on getting a letter to his pa in the Nevada gold fields. Thompson carries the letter, brings back a reply, and hopes to go back for Pa, too—in time for Christmas. Older readers may wonder whether Pa will master skiing in rough terrain in time to make the journey; otherwise, an interesting vignette from the past. Sandin's cheerful, generalized illustrations, crisply silhouetted against the white pages/snow, add appeal. (Easy reader. 5-9)