In this Second Edition each chapter was modified to reflect the changes made to the 1993 AISC LRFD Specifications and the 1994 LRFD Manual of Steel Construction. This book has been written to serve as an undergraduate-level textbook for the first two structural steel design courses in civil engineering. Chapters 1 to 6 contain most of the material taught in the first steel design course and chapters 7 to 11 contain material to meet the needs of the each professor. Review material needed for a thorough understanding of principal axes involved in column and beam behavior are included, as well as formulas for the warping and torsional constants of open sections. This book gives students a brief but realistic introduction to elastic analysis and design of unbraced frames in the LRFD approach.