Most epidemiology workbooks are used as supplements to existing texts. The student reads the chapter, finds the answers, and fills in the right blanks. This is good for understanding basic principles and methods, but for students looking for real-world examples to sharpen their skills, there is Exercises in Epidemiology. The books seven chapters cover issues such as rates and proportions, causal inference, confounding, cohort studies, case-control studies, multiple causal pathways and effect modification, and screening.