Randolph Quirk & C. Wrenn 
An Old English Grammar [PDF ebook] 

This book is designed especially for the literary student of English, and provides a single compact grammar primarily concerned with Classical Old English, rather than the other Old English dialects. The book takes a descriptive approach and avoids assuming a knowledge of Germanic philology. The introduction provides a minimum background of knowledge and indicates the kinds of evidence on which the grammatical description is based.