This third Australian edition has been directed specifically to the design of steel structures in accordance with the Australian standard AS4100-1990 and its Amendments 1, 2 and 3. The removal of material on British and American methods of design has allowed the inclusion of additional material relevant to Australian practice, and of more detail in the worked examples. Thus, Australian designers, teachers and students will find greater clarity and more helpful material. The previous Chapter 7 has been divided into two new chapters: Chapter 7 on Beam-Columns, and Chapter 8 on Frames. The latter has been significantly expanded, both with new material and worked examples, and also with material on frame buckling from the previous Chapter 3. Torsion is now dealt with in Chapter 10. It includes new materials on designing for torsion and for combined torsion and bending, which is based on recent research. Chapter 9 on Connections has been expanded by including material on standardized Australian connections. The preparation of this third Australian edition has provided an opportunity to revise the text gernally to incorporate the results of recent findings and research. This is in accordance with the principal objective of the book, to provide students and practising engineers with an understanding of the relationships between structural behaviour and the design criteria implied by the rules of design codes such as AS4100.