Journal publications are scientific communications intended to convey research results, opinions, observations, and hypotheses. Scientific research is conducted as a part of finding a solution to a problem, which includes issues concerned with public health and identifying new avenues in solving an existing area of concern. In the era of emerging and re-emerging infectious diseases, there is a great demand for clinical research throughout the world. The potential of clinical research as a subject cannot be defined in a single paragraph. The role of clinical researchers in patient care and public health assumes greater significance in recent times owing to many factors that include emerging and re-emerging diseases. This book is a compilation of review communications related to clinical research. This is a conscious attempt intended for enlightening young and budding researchers, providing them with a good idea about the various types of research and clinical research studies.