1 Statement of the Problem.- 1 Historical Introduction.- 2 Designs for a Prototype Cerebral Cortex.- 2 Reviews Of The Experimental Evidence Relevant To The Formulation Of The Theory Of Cortico-Hippocampal Interaction.- 3 Anatomy of the Hippocampal Complex and Related Regions.- 4 Discovery and General Behavioural Correlates of the Hippocampal Theta Rhythm.- 5 The Septum as a Pacemaker for the Hippocampal Theta Rhythm.- 6 Subdivision of Theta Types According to Sources of Extra-Hippocampal Control.- 7 Evidence for Multiple Sources of Theta Generation in the Hippocampus and Related Structures.- 8 Towards a Neuronal Model to Account for the Laminar Waveforms of Theta Activity.- 3 The Theory of Resonant, Self-Organizing Phase-Locked Loops.- 9 Cortico-Hippocampal Interaction: Theory, Implications and Predictions.- 10 Theta Activity and Learning.- 11 Synopsis and Epilogue.- References.