Herbert H. Clark (Herb Clark) is a psycholinguist who serves as Professor of Psychology at Stanford University. Clark is known for his theory of "common ground": individuals engaged in conversation must share knowledge in order to be understood and have a meaningful conversation (Clark, 1985). Together with Deanna Wilkes-Gibbs (1986), he also developed the collaborative model, a theory for explaining how people in conversation coordinate with one another to determine definite references. Clark's books include Semantics and Comprehension, Psychology and Language: An Introduction to Psycholinguistics, Arenas of Language Use and Using Language. After receiving a B.A. with distinction from Stanford University in 1962, Clark went to Johns Hopkins University where he received an M.A. and Ph.D. in 1964 and 1966 respectively. Additionally, in the summer of 1966, he completed his post-doctoral studies at the Linguistics Institute of UCLA.