This book constitutes the proceedings of the 12th International Conference on Industrial and Engineering Applications of Artificial Intelligence and Expert Systems, IEA/AIE'99, held in Cairo, Egypt, in May/June 1999.The 91 revised papers presented together with three invited contributions were carefully reviewed and selected from more than 140 submissions. The book offers sections on fuzzy systems, neural networks, genetic algorithms, searching, reasoning, expert systems, case-based reasoning, intelligent agents, distributed artificial intelligence, pattern recognition and vision, machine learning, temporal reasoning, knowledge representation, planning and scheduling, tutoring and manufacturing systems, and intelligent software engineering.