This book is a contribution to research into the analysis of academic English. It focuses on concrete evidence of change in the syntactic structure of sentences and sentence complexity over a period of about a century. It analyses academic texts from the fields of psychology and economics. Unlike most current research into academic English which focuses on selective syntactic issues, this book offers analyses of stretches of continuous running texts and categorises every single explicitly expressed finite and non-finite predication which occurs in them. The detailed examination of these texts and especially the diachronic perspective which this study adopts reveal and pinpoint some discernible trends in the modes of expression of current academic English, which may remain unnoticed if the research focuses merely on selective issues. This book is intended mainly for professionals and students of linguistics, but it should also be of interest to anyone concerned with academic English, language change and corpus linguistics.