Tufte may be interested in the theory of presentation of information, but that does not make him an 'information theorist'. That title is reserved for those that, eg., publish in the rarified world of IEEE Transactions on Information Theory.
Information theory is the mathematical foundation of compression and transmission of information, started by the venerable Claude Shannon in the late 40's with his paper "A Mathematical Theory of Communication" in The Bell System Technical Journal, Vol. 27, pp. 379-423, 623-656, July, October, 1948.
Tufte may be interested in the theory of presentation of information, but that does not make him an 'information theorist'. That title is reserved for those that, eg., publish in the rarified world of IEEE Transactions on Information Theory.
Information theory is the mathematical foundation of compression and transmission of information, started by the venerable Claude Shannon in the late 40's with his paper "A Mathematical Theory of Communication" in The Bell System Technical Journal, Vol. 27, pp. 379-423, 623-656, July, October, 1948.