This book examines the nature of scientific research : reviews the arguments for and against a normative theory of discovery; describes the evolution of the BACON programs, which discover quantitative empirical laws and invent new concepts; presents programs that discover laws in qualitative and quantitative data; and ties the results together, suggesting how a combined and extended program might find research problems, divise new instruments, and invent appropriate problem representations. Numerous prominent historical exemples of discoveries in physics and chemistry are used as tests for the programs and anchor the discussion concretely in the history of science. – I. Introduction to the theory of scientific discovery : 1, What is scientific discovery ?; 2, On the possibility of a normative theory of discovery; – II. The Bacon programs : 3, Discovering quantitative empirical laws; 4, Intrinsic properties and common divisors; 5, Symmetry and conservation; – III. Qualitative laws and models : 6, Discovering qualitative laws; 7, Constructing componential models; 8, Formulating structural models; – IV. Putting the picture together : 9, An integrated view of law discovery; 10, Discovering problems and representations; 11, Envoi. M.-M. V.