This chapter introduces the major themes of the book: grammatical change in writing, grammatical complexity, and academic writing in English over the past 300 years. The chapter surveys previous research on these topics, and sets the stage for the analyses in the following chapters by highlighting the distinctive linguistic characteristics of academic writing, both across time (19th century vs. present-day) and discipline (humanities vs. science). Through extensive textual examples, we demonstrate that academic writing styles have undergone major linguistic change over the past few centuries, and that these changes have not occurred uniformly across disciplines, findings which contradict previous claims and assumptions about academic writing. Thus, this chapter explores four major stereotypes about academic prose that will be challenged with the corpus-based analyses in this book: (1) all kinds of academic prose are essentially the same; (2) academic prose employs complex and elaborated grammar; (3) academic prose is maximally explicit in meaning; and (4) academic prose is conservative and resistant to linguistic change. Along the way, we challenge two basic theoretical assumptions in previous linguistic research: that grammatical complexity is equivalent to structural elaboration, realized through the use of dependent clauses; and that grammatical changes are initiated in speech and not in writing. We instead argue that historical change can occur in writing.