About the Santa Fe Institute , Santa Fe Institute Editorial Board September 1990 , Santa Fe Institute Studies in the Sciences of Complexity , Series Foreword , Foreword , Foreword , Preface , Introduction , The Hopfield Model , Extensions of the Hopfield Model , Optimization Problems , Simple Perceptrons , Multi-Layer Networks , Recurrent Networks , Unsupervised Hebbian Learning , Unsupervised Competitive Learning , Formal Statistical Mechanics of Neural Networks , Statistical Mechanics