Wikimedia
Wikipedia: Meisner Technique
Encyclopedia article about the Meisner Technique of acting. Along with a brief history, there is a good explanation of the key characteristics, which include living in the moment and spontaneity.
Other
Epstein's Acting Studio:history of the Meisner Technique
Brief history and explanation of the Meisner Technique from an acting studio that specializes in it. Also includes one small picture of Meisner.