This textbook provides an introduction to gravitational lensing which has become an invaluable
tool in modern astrophysics with applications that range from finding planets orbiting distant
stars to understanding how dark matter and dark energy conspired to form the cosmic structures
we see today. Principles of Gravitational Lensing begins with Einstein's prediction that
gravity bends light and shows how that fundamental idea has spawned a rich field of study over
the past century.The gravitational deflection of light was first detected by Eddington during a
solar eclipse in May 1919 launching Einstein and his theory of relativity into public view.
Yet the possibility of using the phenomenon to unlock mysteries of the Universe seemed remote
given the technology of the day. Theoretical work was carried out sporadically over the next
six decades but only with the discovery of the system Q0957+561 in 1979 was gravitational
lensing transformed from a curiosity of general relativity into a practical observational
tool.This book describes how the three subfields known as strong lensing weak lensing and
microlensing have grown independently but become increasingly intertwined. Drawing on their
research experience Congdon and Keeton begin with the basic physics of light bending then
present the mathematical foundations of gravitational lensing building up to current research
topics in a clear and systematic way. Relevant background material from physics and mathematics
is included making the book self-contained.The derivations and explanations are supplemented
by exercises designed to help students master the theoretical concepts as well as the methods
that drive current research. An extensive bibliography guides those wishing to delve more
deeply into particular areas of interest. Principles of Gravitational Lensing is ideal for
advanced students and seasoned researchers looking to penetrate this thriving subject and even
contribute research of their own.
