 Our knowledge of bonding and structure becomes more and more scanty and unreliable for larger structures.A huge amount of research remains to be done if we are ever to be able to describe bonding and structure very accurately for even microscopic amounts of complex substances.Le Roy stated “... except for the simplest systems, our knowledge of (interactions between molecules) is fairly primitive... .” A classic example is our understanding of the structure and activity of proteins—the stuff of life.