Basic Theory of Structures provides a sound foundation of structural theory. This book presents the fundamental concepts of structural behavior. Organized into 12 chapters, this book begins with an overview of the essential requirement of any structure to resist a variety of loadings without changing its shape. This text then examines the application of the laws of statics to structures as a means of determining the external reactions induced at supports due to loading. Other chapters consider the dependence of stress components on the choice of reference plane. This book discusses as well the method of determining the internal forces in the bars of a truss, which depends upon applying the conditions of equilibrium. The final chapter deals with the variety of factors affecting the strength of concrete. This book is intended to be suitable for civil engineering students. Design and civil engineers will also find this book extremely useful.