This book brings together a series of contributions to the study of grammaticalization of tense, aspect, and modality from a functional perspective. All contributions share the aim to uncover the functional motivations behind the processes of grammaticalization under discussion, but they do so from different points of view.
Buy The Grammaticalization of Tense, Aspect, Modality and Evidentiality: A Functional Perspective by Kees Hengeveld from Australia's Online Independent Bookstore, BooksDirect.