The goal of analytical processes is to acquire chemical information and therefore the amount of information, according to Shannon, is the most adequate measure in the evaluation of an analytical process. The procedure of evaluating the amount of information In analytical processes as well as the utilization of this quantity as a criterion in solving many analytical problems is discussed; the problems are: selecting one method out of several methods, the optimal combination of several methods to solve an analytlcal problem, coding of information, and chemical classificatbn. The analogy between the systems of Information transmisslon and analytical measuring systems allows the adaptation of information theory notions (entropy, amount of information, coding, decoding, perturbatlons, etc.) to chemical analysis. This represents the generalized basis of analytical chemistry.(60-63).