This book contains an extensive study of hypersonic boundary layer flow. It focuses predominantly on attachment lines. Attachment lines are present at the leading edges of all aerospace vehicles. Heat transfer at the attachment line is of vital importance especially during upper atmosphere space re-entry. This work considers laminar and turbulent flows with wall suction and blowing. A recovery factor analysis is also presented covering a range of hypersonic Mach numbers. This book is an invaluable aid in aerospace vehicle design and spacecraft performance. It can readily be used for design optimization and aerospace vehicle heat transfer analysis. This work is particularly applicable to undergraduate and post graduate students, researchers and academics in both Aerospace and Mechanical Engineering as well as engineering professionals working for global aerospace and astronautic organizations.