The Scope of Proteomic and Chemical Proteomic Studies, Mass Spectral Studies of Proteome and Subproteome Mixtures, Protein-Protein (or Peptide) Interactions: Studies in Parallel and with Mixtures, Chemical Proteomics: Studies of Protein-Ligand Interactions in Pools and Pathways, Structural Proteomics: Parallel Studies of Proteins, Summary of Chapters and Future Prospects for Spectral Techniques in Proteomics