Explores the question of whether or not concepts and principles involving supernatural intelligent design can occupy any legitimate place within science.Although the scientific illegitimacy of supernatural design is typically asserted with enormous confidence and vigor there has been surprisingly little actual work on such key foundational issues as even what design is and on specific criteria for assessing its legitimacy or lack as a scientific concept. However intelligent supernatural design is again surfacing in discussions both of anthropic principles and of certain types of biological complexity. This book develops a definition of design explicates the more specific concept of supernatural design defends a general criterion for scientific legitimacy and argues that in some cases the concept of intelligent supernatural design can meet the relevant requirements for scientific legitimacy.