Book excerpt: Phenology is the study of plant and animal life cycle events, which are triggered by environmental changes, especially temperature. Wide ranges of phenomena are included, from first openings of leaf and flower buds, to insect hatchings and return of birds. Each one gives a ready measure of the environment as viewed by the associated organism. Thus, phenological events are ideal indicators of the impact of local and global changes in weather and climate on the earth's biosphere. Assessing our changing world is a complex task that requires close cooperation from experts in biology, climatology, ecology, geography, oceanography, remote sensing and other areas. This book is a synthesis of current phenological knowledge, designed as a primer on the field for global change and general scientists, students and interested members of the public. With contributions from a diverse group of over fifty phenological experts, covering data collection, current research, methods and applications, it demonstrates the accomplishments and potential of phenology as an integrative environmental science.