This book primarily examines verbal prefixes expressing aspectuality in the Old and Middle English periods, but it also takes a look at the post-verbal particles in the subsequent periods of English. Verbal prefixes are also known as preverbs such as ge- in the Old English verb gegladian «cheer up» or a- in the Old English verb astreccan «stretch out». Prefixed verbs in Old English are said to be the functional equivalents and predecessors of phrasal verbs in Modern English. One of the aims of the research presented in this book was to consider how no longer productive Old English verbal prefixes such as ge-, a- and for- were used in the past to express verbal aspect. In this study two avenues of research converge, one covering aspect, the other covering verbal prefixes and particles.