If the input symbols to a communication channel represent the outcomes of a chance event on which bets are available at odds consistent with their probabilities (i.e.,"fair" odds), a gambler can use the knowledge given him by the received symbols to cause his money to grow exponentially. The maximum exponential rate of growth of the gambler’s capital is equal to the rate of transmission ofinformation over the channel. This result is generalized to include the case of arbitrary odds.