As thousands of biologically active peptides have been discovered in the last 50 years, to date no one contests that all living organismsfrom bacteria to mammals and complex plant formsproduce such compounds for vital purposes. A few examples are given in Table 16.1.In association with the first discoveries of biologically active peptides, it was noted that natural sources could provide quite restricted amounts of them. At that time, the composition and structure of proteins were not sufficiently understood and the ribosomal machinery remained unknown. Hence, many first-rate chemists started searching for methods, procedures, and protocols that could allow for the preparation of peptides in a variable range of scales and purities. Such circumstances turned peptide synthesis into an important research topic [1,2].In the following decades, peptide synthesis reached a high level of efficacy, and also became a fundamental tool for research in the chemistry and biology of these macromolecules [1,3]. Indeed, most of the current knowledge on peptide hormones, antibiotics, cytotoxins, opioids, and hormone-releasing factors has been generated with the help of synthetics.Peptide synthesis has also been critical for providing a wide range of information in biochemistry, medicine, biology, and chemistry as its applications include: (i) therapeutic purposes [4,5]; (ii) development of techniques for peptide detection, separation, identification, quantification, and analysis [6, 7]; (iii) characterization of proteinase-substrate or inhibitor interactions [8,9]; (iv) study of protein-protein interactions and the basis of protein folding [10,11]; (v) mapping of protein epitopes [12, 13]; (vi) mimicking of enzyme activity [14, 15]; (vii) engineering of new peptide-based drugs with therapeutic potential [16, 17]; (viii) design of new biomaterials [18, 19]; (ix) synthesis of prodrugs [20, 21]; and (x) chemical synthesis of proteins [22, 23].Despite these advances, peptide synthesis remains a research topic that attracts an impressive number of scientists worldwide. Most current studies focus