I love the Hellboy movies. I am a huge Del Toro fan (the man who directed the movies) but even more so I love the character that is Hellboy. He's witty and human despite the fact that he's a demon from Hell.
I can guess that this is the book that inspired the first movie. The plot is not exactly similar but enough that you can put two and two together and get about 3 1/2. The book shares some of the origin of Hellboy and follows him as he tries to uncover what happened to his "father". The story includes Abe and Liz but they are so secondary that you are left wondering why anyone bothered with them in the first place - they really are just tools to move along the plot.
I have to say I prefer the movie but then graphic novels really have a problem when it comes to development. I love graphic novels but they don't have the same character insight and they really have a far more basic plot than a book or movie. They are similar to tv shows in that they rely on longevity. Graphic Novels are never meant to stand alone (with a few exceptions).
With all that said, I can't really share the plot with you because it's such a small plot that anything I share would ruin it. I did love it. Hellboy is still Hellboy and I look forward to future stories and future movies now that you mention it.