Transistors reviews major advances that have been made with respect to transistors and illustrates some of the many facets of transistor research and development. Topics covered range from point contact devices and junction devices to p-n junctions in semiconductors, unipolar and analog transistors, and hole injection in transistor action. The physical principles involved in transistor action are also discussed, along with the nature of the forward current in germanium point contacts. This book is comprised of 19 papers and begins with a summary of the semiconductor physics pertinent to the understanding of transistors. The reader is then introduced to developments in point contact devices and junction devices; how the conductance of thin films of semiconductors is modulated by surface charges; the relation between surface states and rectification at a metal-semiconductor contact; and a three-element electronic device that utilizes a semiconductor as the basic element. The remaining papers focus on p-n junction transistors; the theory of alpha for p-n-p diffused junction transistors; and unipolar and analog transistors. The effects of electrical forming on the rectifying barriers of n- and p-germanium transistors are also analyzed. The final chapter describes a thin-film transistor fabricated by evaporation of all components onto an insulating substrate. This monograph will be of interest to physicists and electronics engineers.