The book attempts to present the topic of monoclonal antibodies, a biotechnological innovation that holds immense potential in the field of diagnostic and therapeutic medicine in a nutshell. The various aspects like the development of mAbs through hybridoma and phage display technologies, therapeutic applications in various fields of medicine and potential serious adverse effects are presented in a concise, interesting manner. Complex technical detail has been curtailed in an effort to make reading the book more enjoyable and less tedious. Nonetheless, a basic knowledge of human biology would be of help in understanding the material. For readers who require a more detailed and extensive understanding of the subject and for further reading, the references provided would serve as useful resources. A modicum of information regarding the therapeutic potential for mAbs in the treatment of COVID 19 has been provided on account of the currently raging pandemic which is causing a global frenzy of effort for a cure.