Dr. David J Smith BSc, PhD, CEng, FIEE, HonFSaRS, FIQA, MIGasE, has been directly concerned with reliability, safety and software quality for 30 years. He has written a number of books on the subject as well as numerous papers. His PhD thesis was on the subject of reliability prediction accuracy and common cause failure. He chairs the IGasE panel which develops its guidelines on safety-related systems (now in its third edition). He has also made contributions to IEC 61508.