C.S. Forester, The Hornblower Companion (1964). The first edition I have in front of me has become very collectible and pricey. Fortunately, it has been reprinted in paperback, a used copy of which can be had for a few dollars (or pounds).
This is a wonderful book. No, actually two wonderful books. The subtitle says it all: An Atlas and Personal Commentary on the Writing of the Hornblower Saga, with Illustrations and Maps by Samuel Bryant.
The first part of the book consists of thirty detailed maps covering HH's entire naval career, with a paragraph or two of commentary and analysis. The maps and the margins of their facing pages are adorned with Bryant's exquisite pen-and-ink drawings. He does a masterful job illustrating both ships and people. The pleasure of examining these little gems never seems to fail. (I have the privilege to own the original ink drawings of three of the maps -- numbers 17, 22, and 27 -- each with all the drawings that grace the facing page of the book. They also have corrections and annotations in CSF's handwriting.)
Forester modestly entitles the remainder of the book, some 90 pages, Some Personal Notes. Forester opens his mind to us and describes the writing process in real depth, discussing how he gets ideas, how they come together in to books, his writing regimen, and the writing/publishing history of the Hornblower books. Absolutely fascinating. And, I should think, required reading for all contemporary writers of Historic Naval Fiction. This book is a must for both readers and writers of HNF.
Description of: The Hornblower Companion
Author: C. S. Forester