The brain transforms information in two competingways. Automatic processing runs independently ofcurrent goals and is based on the long-term encodingof patterns and expectations. Controlled processingis the modulation of automatic processes to reach adesired outcome, when that might not be achieved byautomatic processing alone. The interplay betweenthese processes plays an important role indetermining our behaviour and internal mental states.Converging lines of evidence suggest that the controlof information processing is associated with rhythmicpatterns in brain activity. Following a discussion ofthis evidence, several experiments are presented inwhich brain activity during control was studied usingthe EEG. This high time-resolution measure of neuralprocessing allowed event-locked waveforms,fluctuations in the amplitude of oscillatory activityand the between-trial consistency of phasedifferences between signals to be measured. The bookshould be of use to researchers and students incognitive neuroscience or others with an interest inthe neural activity associated with cognitive control.