The difficulty surrounding historical studies of modern science in Asia, especially in East Asia, induces an impulse to describe modern science in Asia more simply than it actually was. In the nineteenth century, modern science began to be introduced actively to East Asia. So then, how should its historical environment be visualized? How can the framework of the nation-state be positioned in that context? The edited volume Essays on the History of Scientific Thought in Imperial Japan adopts the word empire in its challenging attempt to answer these questions. In an era when Japan was expanding and becoming an empire, how did people in East Asia face science and technology of Western origin? How was it adapted and institutionalized? And how was the remnant that could not be included within science and technology extracted socially? All these questions are examined in this book. Its attempts to describe the process of the spread of modem science are based on experiences gained from a series of studies rooted in the Needham Question, which examines the process together with the simultaneous spatial expansion of Westem Europe. How was the spread of science and technology during an age of Western expansion and colonization experienced both in Western society and in other regions including colonized space? The studies in this book consist of extraordinary chains of rereading of historical materials of memories, often recorded as individual experiences in various forms.