In medieval Europe, the natural world was referred to as the “Book of Nature,” which was considered to supplement the Bible as a guide to divine will. Scripture and nature were alternative expressions of God’s message and purpose for humanity. There were thus two testimonials to the Creation: the Bible and the natural world itself. Study of nature meant attention to the miraculous and portentous; like scripture, the Book of Nature was read for its prophetic value, not out of dispassionate curiosity. Protestant scientists in particular, who rejected the priesthood and hierarchy of the Church and slavish devotion to past scholarship, wanted to read and interpret the Bible for themselves—and equally the Book of Nature. Both were to be taken more literally and freed from the fancies of medieval interpretation. Early science hardly breaks with medieval tradition concerning the Book of Nature but implicitly regards nature as a text to be deciphered. New interest in the study of languages encouraged a more formal approach to the natural world. Galileo proclaimed the Book of Nature to be written in the language of mathematics. Equations and theories are literally texts. To the degree we identify them with natural reality, the world itself is implicitly conceived as a text. The advantage of this way of seeing the world is control: scientific models and mathematical equations facilitate prediction and the control necessary for technology. Like machines, models and equations are human constructions. They are finite and well defined, products of definition. Natural phenomena are sought ought that can be treated effectively in terms of such constructs. But this may represent only a small part of natural reality. Only recently, for example—with the aid of the computer—have complex systems begun to be studied. Previously, simple systems were considered because they could be modeled by equations that could be solved with pencil and paper. The world may turn out not to resemble a book—or any other text, such as a computer program.