Given the facts that only committed Hellboy fans are likely to buy this book and committed Hellboy fans would buy it pretty much regardless of the quality, this is accessible, entertaining and a treat for any Hellboy fan. In keeping with the quality control exercised throughout the franchise, this is thoughtful, well produced and literate. It does a very nice job of both extending and explaining the literary roots and context of Hellboy and diving headfirst into the details and revelling in them.
The core of the book are the character profiles by Victoria Blake and Rachel Edidin, these cover just about every character who cross any page in any Hellboy or B.P.R.D. book. This should be inaccessible to anyone but a committed fan and possibly even a step too far for a lot of them. Thanks to fine writing by Victoria Blake and Rachel Edidin this is a series of intriguing micro biographies of a wonderfully assorted cast of characters. There is a notable absence of referential defensiveness in the writing, the reader does not have to possess a degree of prior knowledge to enjoy the profiles. They are informative and comprehensive, the various illustrations, old and new, from Mike Mignola, has been chosen with care.
The Official Timeline by Jason Hall is really for committed fans only, it is also just fantastic. It has the correct level of detail, catches all the highways and byways that are explicit and implicit in the stories and creates a breathtaking view of the world of Hellboy. The Literary Heritage of Hellboy, an essay by Stephen Weiner, and the Further Reading section round of the volume in fine style with the essay showing the breath and depth of the influences and sources that Mike Mignola lovingly draws upon for his work.
I read this book straight through, I appreciated and enjoyed the authors care, attention and talent and they have increased my enjoyment of the various Hellboy comics and films greatly.