The 7th installation in the Hellboy graphic novel releases is something good to acquire, BUT acquiring it depends on what you want from your Hellboy.
First and foremost, the stories herein are mostly collected tales from fragmented places. The Troll Witch, The Hydra and the Lion, Doctor Carps Experiment, and The Ghoul are pieces from the "Dark Horse Book(s) of the..." (Witchcraft, Monsters, Hauntings, and The Dead respectively). These range from five to eight pages depending, and all of them have something to offer. The best piece in the book HAS to be The Troll Witch, and I personally liked Doctor Carp as well. The Ghoul is a Shakespeare adaptation and the Hydra and the Lion is, as Mignola admits in its forward, a bit odd. If you want these and don't want to pick up all of those books, then this is a good way to do it.
Second, there is some random stuff here and some new stuff BUT some of it isn't the best stuff out there.
The Penanggalan is an older story that came out of a Wizard magazine release, and covers a beast spawned from Malaysian folklore. It is a big odd but also a bit predictable, covering ground that Hellboy covered back in 2004. The Vampire of Prague is unique to this series but isn't really one of my favorites. P. Craig Russell did the artwork and, to be frank, it looks a bit rudimentary. When reading Hellboy I guess I've been spoiled and I want Mignola to cover every aspect. The story is small, good to read but normal, and Mignola could have sealed it for me and didn't. I guess that's something that is up to individual tastes.
And the last is Makoma, the longest addition to the book by far, covering some of Hellboy's younger years when he was in Africa. I liked the story and liked the quest artwork of Richard Corben, with everything clicking in that folklore sense that Hellboy often delivers. There's a mixture of Mignola there, too, and that made it worth a read.
And the extras - little etchings of characters and rudimentary cover art - don't really make me want to invest in Graphic Novels. I DO enjoy the forwards that come before each story, telling where the ale came from and how people became involved therein. Mignola is nothing if not a storyteller and this aspect adds to the read.
All that said, I enjoyed the series and thought people would enjoy it as well depending on what they want. If you missed the Dark Horse Book of series then there's a lot of tales here that are interesting and this format is a lot cheaper to acquire. The additions are good but are not necessary in pushing out a storyline and the book, on the whole, is just fragmented tales that cover some of Hellboy's adventures.
Keep that in mind before purchasing.