This acclaimed book covers the principles and methodologies in adaptive design and analysis that pertain to adaptations made to trial or statistical procedures based on accrued data of ongoing clinical trials. It presents a well-balanced summary of current regulatory perspectives, recently developed statistical methods, and statistical tests for seamless phase II/III adaptive designs. This edition features two new chapters as well as a complete rewrite of the chapter on computer simulation. It also includes computer simulations and various case studies to ensure a practical understanding of the methodologies.