This book covers different physiological processes, tools, and their application in crop breeding. Each chapter emphasizes on a specific trait/physiological process and its importance in crop, phenotyping of information, and how best such information can be employed for crop improvement by projecting on success stories in different crops. The volume covers wide range of modern-day physiological topics, including advances in field phenotyping, metabolomics, application of stable isotopes, and phenomics. It also covers futuristic research areas like artificial intelligence and machine learning. Topics on photosynthesis such as photorespiration and photoperiodism are also covered in the subsequent chapters. This contributed volume compiles all application part of physiological tools along with their advanced research in these areas, which is very much need of the hour for both academics and researchers for ready reference. This book will be of interest to teachers, researchers, climate change scientists, capacity builders, and policy makers. Also, the book serves as additional reading material for undergraduate and graduate students of agriculture, physiology, botany, ecology, and environmental sciences. National and international agricultural scientists will also find this a useful resource.