In the behavioral and clinical sciences, single-subject designs have increasingly become important tools for determining a treatment efficacy. Despite a large number of recommendations in recent years for more use of the designs, the majority of typical research methods textbooks still do not provide sufficient direction and information about single-subject designs. One of the main reasons is that data analysis of single-subject designs is still foreign to the vast majority of the investigators, practitioners, and students. The authors have developed a practical guide of the most commonly used approaches in analyzing and interpreting single-subject data. In doing so, they have arranged the methodologies used in a logical sequence using an array of research studies from the existing published literatures to illustrate specific applications. The handbook is also laid out for the readers in a highly lucid and straightforward manner, beginning with a brief discussion of each approach such as visual, inferential, and probabilistic model, the applications for which it is intended, and a step-by-step illustration of the test as used in an actual research study. Presented is a brief evaluation of the strengths and limitations of the test along with its suitability, or lack thereof, for particular scales of measurement. Also included are statistical applications of such computer programs as Minitab and SPSS for the analysis of statistical data. This new handbook provides the readers with a concise yet comprehensive approach to help them further understand the concepts as effectively and simply as possible.