The Altadena main library hosts Violinist Paul Stein and Chamber Music Express, 7 p.m. Monday, Dec. 10.  Stein and the Chamber Music Express blend music and imaginative storytelling, entertaining children and adults alike. The beauty and logic of music have much in common with math. The music of Mozart, Kreisler, and Brahms will share the program with gypsy music by Drdla and John Williams’ Harry Potter. And as an added bonus, there will be some memorable story problems. Appropriate for children ages 6 and up. This event is sponsored by the Friends of the Altadena Library.