Critical beam intensity issues in hadron colliders

I would like to discuss how some of the issues that have been talked about at this workshop (and some that haven`t) are reflected in the performance of hadron colliders. Hadron colliders, be they proton-antiproton, proton-proton, or heavy ion, are typically supported by a half-dozen other accelerators each of which has its own set of performance characteristics and limitations. As a result, when designing, building, operating, or upgrading a hadron collider choices must be made that determine not only overall performance but also the ultimate configuration of the complex. It is impossible to discuss here the full range of issues that one has to consider in projecting performance in a hadron collider. I will concentrate on a few and attempt to make some observations on how/when various effects relating to beam intensity are important. We will start with a short introduction that is intended to give the ``lay of the land`` in hadron colliders--what are the performance issues and what are the fundamental mechanisms that limit performance? We will then examine how choices in beam parameters can and have influenced performance, and how strategies are likely to change as we contemplate higher energy colliders. Finally, I will offer some opinions on what research directions are dictated for improving the luminosity delivered from hadron colliders