The development of therapeutic antibodies has seen significant advancements over the past three decades, with the first monoclonal antibody approved by the US FDA in 1986. This review highlights the evolution of antibody engineering and its increasing role in treating various diseases, including cancers, autoimmune, metabolic, and infectious diseases. The global therapeutic monoclonal antibody market is projected to grow from $115.2 billion in 2018 to $300 billion by 2025. Key technologies in antibody engineering include humanization of monoclonal antibodies, phage display, transgenic mice, and single B cell antibody technology. Phage display, in particular, has been instrumental in discovering and developing fully human therapeutic antibodies, with nine such drugs currently approved by the US FDA. The review also discusses the clinical applications and market trends of therapeutic antibodies, emphasizing their importance in treating diseases such as cancer, rheumatoid arthritis, and infectious diseases. Additionally, it covers the methodologies for developing therapeutic antibodies, including humanization techniques and affinity maturation methods, to enhance their safety and efficacy.The development of therapeutic antibodies has seen significant advancements over the past three decades, with the first monoclonal antibody approved by the US FDA in 1986. This review highlights the evolution of antibody engineering and its increasing role in treating various diseases, including cancers, autoimmune, metabolic, and infectious diseases. The global therapeutic monoclonal antibody market is projected to grow from $115.2 billion in 2018 to $300 billion by 2025. Key technologies in antibody engineering include humanization of monoclonal antibodies, phage display, transgenic mice, and single B cell antibody technology. Phage display, in particular, has been instrumental in discovering and developing fully human therapeutic antibodies, with nine such drugs currently approved by the US FDA. The review also discusses the clinical applications and market trends of therapeutic antibodies, emphasizing their importance in treating diseases such as cancer, rheumatoid arthritis, and infectious diseases. Additionally, it covers the methodologies for developing therapeutic antibodies, including humanization techniques and affinity maturation methods, to enhance their safety and efficacy.