"The World of Peptides" is a specialized book that focuses on the significant role of peptides in biological processes. While proteins have been recognized as essential components of life for nearly two centuries, the understanding of the diverse functions of peptides has greatly increased in recent decades. This book highlights the discoveries of biologically active peptides in various organs, including the brain and heart, as well as their presence in toxins and antibiotics. It becomes clear that the chemistry of peptides must be regarded as a distinct discipline within biochemistry, separate from the chemistry of proteins. The synthesis of peptides plays a crucial role in both research and practical applications, further enriching the field of bio-organic chemistry. Given the continuously growing knowledge about peptides, it is time to reflect on the development of this new discipline and to acknowledge the key milestones in the history of peptide chemistry.