Practical Manual of Medical Diagnostics (XI) is a comprehensive monograph of the ‘Clinical Diagnostics Manual’ consisting of 20 chapters. The chapters describe the clinical biochemistry methods e.g., Benedict Reagent, Protein Heat Coagulation Test, Rothera’s test, Hay’s Sulphur Test, Benzidine test, and Histopathology techniques of tissue processing. These chapters provide useful information, particularly for beginners in the field to develop background knowledge that is essential for its practical application. The book also includes chapters on body fluid, cerebrospinal fluid circulation, normal and abnormal sperms, prevention of male infertility, and prevention of infectious diseases. The book also includes a chapter on the designing of research or review projects with examples of various topics of disease diagnosis and medical science application e.g., drug discovery process, early screening of lung cancer, detection of SARS-CoV-2 viral load in salivary samples, COVID-19 diagnostic test through RT-PCR, basic methods of nanoparticle synthesis, use of convalescent plasma to treat COVID-19 patients, in vitro fertilization, and hematopoietic stem cell transplant, etc. By studying the book, readers will gain a better comprehension of ethical and safety considerations in medical diagnosis, as well as the principles involved in the interpretation of diagnostic tests. We anticipate that this book will play a role in raising healthcare standards globally.