This book gathers a collection of reprints on the Hubbard Model. The major contributions to the subject since its origin are included, with the aim of providing all scientists working on the model and its applications with easy access to the relevant literature.The book is divided into five parts. The introductory part is concerned with the physical origin and motivations of the model, and contains a collection of mainly historical papers. The remaining four sections are intended to present a coherent scenario of the different approaches to the model solution: exact and rigorous statistical mechanics results; variational methods; perturbative approaches; numerical Quantum Monte Carlo and exact diagonalization studies. Among the applications special emphasis is given to high-Tc superconductivity. Each section is preceded by commentary notes from the editor.