UNDERSTANDING THE HIGH-REDSHIFT UNIVERSE - PROGRESS, HYPE AND PROSPECTS

The baryon content of the Universe, the dark matter, and the cosmic fl uctuations, are legacies of the poorly-understood earliest phases of t he big bang. Observations of large-scale structure and the microwave b ackground are now constraining these key parameters. Quasars and other high-redshift objects allow us to probe the last 90 per cent of cosmi c history, and also have important implications for relativistic astro physics. Our confidence in any model of the ultra-early Universe is li mited by our ignorance of the relevant basic physics; complexities of a different kind confront attempts to interpret and simulate the rapid ly-expanding astronomical data on the 'later' Universe.