Annu. Rev. Astron. Astrophys. 1992. 30: 429-456 Copyright © 1992 by Annual Reviews Inc. All rights reserved

Reprinted with kind permission from Annual Reviews Inc., 4139 El Camino Way, Palo Alto, California, USA

Key Words: diffuse background, quasars, large-scale structure, X-ray sources

Table of Contents

INTRODUCTION

THE SPECTRUM OF THE XRB

THE ISOTROPY OF THE X-RAY BACKGROUND

THE CONTRIBUTION OF KNOWN CLASSES OF DISCRETE SOURCES

Surveys at Energies Above 3 keV

Surveys at Energies Less Than 3 keV

Constraints from the Isotropy of the X-Ray Background

Conclusion

MODELS FOR THE RESIDUAL BACKGROUND

A Diffuse Origin?

A New Class of Sources

THE LARGE-SCALE STRUCTURE OF THE UNIVERSE AND THE X-RAY BACKGROUND

SUMMARY AND FUTURE WORK

REFERENCES