Quote from : Starting Strength: Basic Barbell Training Book

You do not need to do many different exercises to get strong - you need to get strong on a very few important exercises, movements that train the whole body as a system, not as a collection of separate body parts. The problem with the programs advocated by all the national exercise organizations is that they fail to recognize this basic principle: the body best adapts to stress applied to the whole organism. The more stress that can be applied to as possible, the more effective and productive the adaptation will be.