Middle-range theory (MRT), as the concept of intermediate theory between observed empirical data and general theories, was first formulated by the sociologist R.K. Merton in the context of the positivist waves of the 1960s as a reaction to the doctrinaire and descriptive paradigms of previous decades. Among the first archaeologists to employ this concept was L.R. Binford, whose work was particularly influential in the subsequent development of MRT in archaeology. Understanding site formation processes and the mechanisms responsible for generating, modifying and destroying traces of the past has been equated with MRT, particularly in Paleolithic archaeology. The development of MRT has played a crucial role in the formation and elaboration of field techniques, research designs, and new methodologies and, as such, has stimulated new directions and new questions in Paleolithic archaeology. This paper elaborates the definition of middle-range theory and discusses its development and application by archaeologists. Relevant components of MRT such as ethnographic analogy, ethnoarchaeology, experimental archaeology, taphonomy, and uniformitarianism are addressed, and some representative case studies are presented.