Author cocitation analysis (ACA) is a subfield of informetrics, which is a broader term referring to the quantitative study of retrieval and processing bibliometric data collected from all types of communication media, including journals, books, and conference proceedings. While ACA is one of the few research methodologies that transcend the individual field of inquiry, and despite its usefulness and capabilities to reveal a larger vista hidden in bibliographic databases, it is not a particularly popular research tool in some academic disciplines. This book covers all essential ACA topics for graduate students and researchers who want to learn the basics and the research techniques to delineate the intellectual structure of various academic disciplines, compare cumulative research traditions, demonstrate theoretical differences between competing approaches, and to trace a paradigm shift in various academic disciplines over time.