I wanted to recommend "The Peregrine" by J.A. Baker. First printed in 1967, now reprinted with an intro by Mark Cocker. Fantastic study based on personal observation, I am learning loads about these magnificent birds.
Hi John, one I've been meaning to read. The new hardback reprint looks really great. J.A. Baker's book is referred to in a book called Findings by Kathleen Jamie, which briefly touches upon Peregrines, amongst other birdlife and wildlife. I think it's a terrific book.
Another recommendation for those interested is The Peregrine Falcon by Derek Ratcliffe. Derek Ratcliffe was involved in studies of the effects of agricultural pesticides on birds of prey and his findings were instrumental in their being phased out.