More than four decades after the first Conference on Multiple Criteria Decision Making (MCDM) in 1972, this field has accomplished some maturity and has drawn closer to a turning point. Many publications, studies and applications around the world have showed how vast is the scope of MCDM. The purpose of this paper is to shed some light on different aspects of MCDM in order to clarify notions and present the field in a holistic way. Its main goal is to serve as an entrance door to future students and researchers, supporting them with an easy and clear approach, which represents a quick survey on the field of decision support, and a guide to an effective and meaningful application of the methods in different areas of research and real world problems.