Statistical methods play an essential role in all stages of a quantitative health care and clinical research from design analysis and interpretation of real life data sets. The clinical trial is "the most definitive tool for evaluation of the applicability of clinical research" It represents“ a key research activity with the potential to improve the quality of health care and management through careful comparison of alternative treatments” It has been called on many occasions "the gold standard" against which all other clinical research is measured. Although many clinical trial are of high quality, a careful reader of the medical literature will notice that a large number have deficiencies in design, conduct, analysis, presentation, and /or interpretation of results. Improvements have occurred over the past few decades, but too many trials are still conducted without adequate attention to its fundamental principles. Certainly, numerous studies could have been upgraded if the authors had a better understanding of the fundamentals. This book covers the essential principles and methods required for clinical research. The underlying concepts of statistical analysis including basic and some more advanced analysis techniques are also covered. This book is an attempt to present the recent statistical techniques and tools with suitable examples from real life data sets, which the clinical researchers and academicians need.