This new third edition of a highly regarded text, discusses the behavior of steel structures and the criteria used in design according to the British code BS5950:2000. Thus it serves to bridge the gap which too often occurs when attention is concentrated on methods of analysis and the sizing of structural components. Because emphasis is placed on the development of an understanding of behavior, many analytical details are either omitted in favor of more descriptive explanations, or are relegated to appendices. The many work examples both illustrate the behavior of steel structures, and exemplify details of the design process.