Ch 1. A clockwork green: circadian rhythms in photosynthetic organisms. Ch 2. Rhythms in organ movements. Ch 3. The cellular organization of circadian rhythms in plants: not one but many clocks. Ch 4. Stomatal rhythms. Ch 5. Genetic approaches to the analysis of circadian rhythms in plants. Ch 6. Molecular analysis of circadian clock-regulated gene expression in plants: features of the 'output' pathways. Ch 7. Carcadian rhythmicity in Neurospora crassa. Ch 8. Photoentrainment in the vertebrates: a comparative analysis. Ch 9. Photoperiodism: an overview. Ch 10. Photoperiodic induction in short-day plants. Ch 11. The photoperiodic control of tuberization in potato. Ch 12. Dormancy: night-timekeeping and day-timekeeping for the photoperiodic control of budset in Norway spruce. Ch 13. Developmental processes in insects: circadian rhythms and photoperiodism in the blow fly, calliphora vicina. Ch 14. Rhythms and photoperiodism in birds. Ch 15. Photoperiodic regulation of flowering time in arabidopsis. Ch 16. Genetic dissection of the photoperiod-sensing mechanism in the long-day plant arabidopsis thaliana.