This is chapter 4 of the book, generally describes risk in agriculture through a study of the available literature, covering such topics as what risk is; estimations of variability in price, yield and off-farm income; causes of variability in agriculture; producer risk perceptions and preferences; and, lessons learned on the magnitude and causal factors of agricultural risks. This chapter comes from the perspective that Agricultural risks are not independent, but rather are linked both to each other and as part of a system that includes all available instruments, strategies and policies designed to manage risk, concluding that a holistic approach is thus necessary.