In the past, pharmaceutical companies have quickly jumped to Phase III without completion and full analysis of Phase II, which consequently led to failure. In the future, more emphasis needs to be placed on quality designed, conducted, and analyzed Phase II clinical trials. Focusing on Phase II clinical trials conducted in a sequential manner, this handbook presents modern techniques of clinical trial design, describes many Phase II designs, and discusses the software used for sample size and power analysis. It also provides sample size tables for those without the appropriate software to calculate sample size and power and includes numerous real-world examples of trial designs in use.