Generations of philosophers and theologians, physicists and mathematicians have wondered and puzzled, speculated and argued about the nature of time. Recent scientific work is said to explain why time runs inexorably forward from past to future. But time still contains many mysteries - black holes and big bangs, asymmetries and relativities, arrows and loops - that will doubtless continue to occupy us for centuries to come. The contributors include philosophers Michael Dummett, Bill Newton-Smith, John Lucas and Michael Lockwood, physicists Paul Davies, Peter Atkins and Michael Shallis, and mathematicians Roger Penrose, Dennis Sciama and Raymond Flood.