Understanding Enzyme Mechanism through Protein Chimeragenesis -- Chemical Protein Engineering: Synthetic and Semisynthetic Peptides and Proteins -- Native Chemical Ligation: SemiSynthesis of Post-translationally Modified Proteins and Biological Probes -- Chemical Methods for Mimicking Post-Translational Modifications -- Noncanonical Amino Acids in Protein Science and Engineering -- Fidelity Mechanisms of the Aminoacyl-tRNA Synthetases -- Specialized Components of the Translational Machinery for Unnatural Amino Acid Mutagenesis: tRNAs, Aminoacyl-tRNA Synthetases, and Ribosomes -- In Vivo Studies of Receptors and Ion Channels with Unnatural Amino Acids -- Synthesis of Modified Proteins Using Misacylated tRNAs -- Cell-Free Synthesis of Proteins with Unnatural Amino Acids. The PURE System and Expansion of the Genetic Code -- Engineering Nucleobases and Polymerases for an Expanded Genetic Alphabet -- Understanding Membrane Proteins. How to Design Inhibitors of Transmembrane Protein-Protein Interactions.