The Drude Theory of Metals. The Sommerfeld Theory of Metals. Failures of the Free Electron Model. Crystal Lattices. The Reciprocal Lattice. Determination of Crystal Structures by X-Ray Diffraction. Classification of Bravais Lattices and Crystal Structures. Electron levels in a Periodic Potential: General Properties. Electrons in a Weak Periodic Potential. The Tight-Binding Method. Other Methods for Calculating Band Structure. The Semiclassical Model of Electron Dynamics. The Semiclassical Theory of Conduction in Metals. Measuring the Fermi Surface. Band Structure of Selected Metals. Beyond the Relaxation. Time Approximation. Beyond the Independent Electron Approximation. Surface Effects. Classification of Solids. Cohesive Energy. Failures of the Static Lattice Model. Classical Theory of the Harmonic Crystal. Quantum Theory of the Harmonic Crystal. Measuring Phonon Dispersion Relations. Anharmonic Effects in Crystals. Phonons in Metals. Dielectric Properties of Insulators. Homogeneous Semiconductors. Inhomogeneous Semiconductors. Defects in Crystals. Diamagnetism and Paramagnetism. Electron Interactions and Magnetic Structure. Magnetic Ordering. Superconductivity. Appendices. Biografía del autor Neil W. Ashcroft is a British solid-state physicist. Ashcroft completed his undergraduate studies at the University of New Zealand in 1958 and received his PhD in 1964 from the University of Cambridge for research investigating the Fermi surfaces of metals. Following his PhD, Ashcroft completed postdoctoral research at the University of Chicago and at Cornell University, where he became a Professor in 1975. In 1990 he was named the Horace White Professor of Physics, and was elected to emeritus status in 2006. He served as the director for the Laboratory of Atomic and Solid State Physics at Cornell University (1979-1984), the director for the Cornell Center for Materials Research (1997-2000), and as the deputy director for the High Energy Synchrotron Source (1990-1997). Between 1986 and 1987, he served as the head of the Condensed Matter division of the American Physical Society. His textbook on solid-state physics, written with N. David Mermin, is a standard text in the field. Since 1997, he has been a member of the National Academy of Sciences.N. David Mermin is Horace White Professor of Physics Emeritus at Cornell University. He has received the Lilienfeld Prize of the American Physical Society and the Klopsteg Award of the American Association of Physics Teachers. He is a member of the U. S. National Academy of Sciences and the American Academy of Arts and Sciences. Professor Mermin has written on quantum foundational issues for several decades, and is known for the clarity and wit of his scientific writings. Among his other books are Solid State Physics (with N. W. Ashcroft, Thomson Learning 1976), Boojums all the Way Through (Cambridge University Press 1990), and It?s about Time: Understanding Einstein?s Relativity (Princeton University Press 2005).