Published in Physics Today, June 1992

Abstract. Most of the matter in the cosmos can't be seen directly at any wavelength. But we can map and weigh great clumps of this dark matter as they bend the light shining through them from distant background galaxies.

Table of Contents

INTRODUCTION

GRAVITATIONAL LENSING

DARK MATTER AND EVOLUTION

THE BACKGROUND GALAXIES

THE FIRST LENSES

GALAXY CLUSTERS AS LENSES

SIMULATIONS

THE INVERSE PROBLEM

ABELL 1689 EXPOSED

REFERENCES