**1. About this book**

This book aims to review the current and latest research outcomes in the field of Pleistocene Archaeology around the world. From our understanding, the major purpose of Pleistocene Archaeology is to research the deep human history of hunter-gatherers before the development of agricultural or Neolithic societies and civilizations during the Holocene. The current geological timeline of the Pleistocene is regarded to be between about 2.58 million years ago and 11,700 years ago [1–3]. It is then followed by the Holocene as the present geological period. In terms of human history during the Pleistocene times, a variety of human species have been existed, and most important for us as modern-day *Homo sapiens* are the emergence, evolution, and dispersal of the genus Homo during this time range.

With such understanding, this book mainly focuses on archaeological studies of our species, from archaic hominins like *H. erectus*, H. *neanderthalensis*, H. *floresiensis*, to *Homo sapiens* as anatomically modern humans (AMH). The main topics of this book are: (1) human migrations in and out of Africa by Homo species, particularly by *Homo sapiens* who migrated into most regions of the world and various environments, (2) the development of human technology from early to archaic Homo species and *Homo sapiens* (e.g. stone and bone tool production and use, ornaments, rock art, hunting, fishing, gathering, resource exchange), and (3) human adaptation to new environments or environmental changes caused by past climate changes during the Pleistocene. With such perspectives in mind, this book contains a total of eight insightful and stimulating chapters related to these topics which review and discuss human history during the Pleistocene times.

It is true that the main human actors during the Pleistocene are Homo erectus and similar archaic hominins as Homo erectus appeared by 2 million years ago (2 Ma) in Africa and existed at least by around 110 ka in Java, Indonesia [4]. Homo erectus or their related species (e.g. H. rudolfensis, H. heidelbergensis, H. ergaster, and possibly H. habilis as well) most probably originated in Africa and are considered to be the first hominin group that succeeded to move "Out of Africa" and migrate into Asia and Europe possibly after [5–7]. Homo erectus and Homo heidelbergensis were also the likely ancestors to Neanderthals (H. neanderthalensis) and Denisovans in Europe and Siberia [8–10], as well as ancestral to small-bodied hominins like H. floresiensis, a recently found species in Flores Island in Indonesia [11] and H. luzonensis another newly discovered species in Luzon Island in the Philippines [12].

Although these facts clearly support Homo erectus and other archaic hominin species can be one of the main targets for Pleistocene Archaeology, this book mainly focuses on migration, technology and adaptation by Homo sapiens as anatomically modern humans. This is partly because of their wider migration area which covered almost the entire inhabitable world and the various and increasingly compex technologies they invented. Therefore, we consider Homo sapiens as the most important species and main actor in our discussion of Pleistocene Archaeology. In fact, Japan including the Ryukyu Islands, Oceania, Australia and New Guinea, and the American continent as the New World were initially reached and colonized by Homo sapiens, and no traces of other Homo species have been found, so far.

Another reason for us to focus on Homo sapiens is the on-going project "Cultural History of PaleoAsia" as the scientific research of a MEXT Grant in Aid Project in Japan (headed by Prof. Yoshihiro Nishiaki during 2016-2020) in which both editors of this book (Ono and Pawlik) have participated since the beginning. This project aims to analyze an extensive set of relevant field and theoretical data from Asia in order to interpret the nature of distinct patterns in the formation of modern human cultures across Asian region after the Out of Africa event, and has already produced a number of publications (e.g. [13–15]). The basic idea and major topics of this book were originally evoked by joining this interdisciplinary project and we are grateful for the opportunity to publish this book in the last year of this important project.
