Toddlers rapidly develop hand and finger skills during their second year of life. They can now manipulate small objects with ease, turning the pages of books, building towers of blocks, and unzipping large zippers.
Shelov, S. P. (Editor-in-Chief). (2004.) Caring for Your Baby and Young Child: Birth to Age 5. The American Association of Pediatrics. Revised edition. New York: Bantam Books.