I've just picked up a pdf copy of Hammer and Forge (http://www.ganeshagames.net/product_info.php?cPath=1_6&products_id=287). This is a supplement for Ganesha Games' Advanced Song of Blades and Heroes (ASOBH), focused primarily on Dwarves.
The price tag is $10, from which you will get a thoroughly illustrated version and an ink-saving copy. From the cover to the back it comes in at 82 pages. Its crammed with lots of fluff, optional rules, new traits, and even a brief Dwarven Dictionary. Whether you decide to play in their game world of Norindaal or not, you will find plenty of ideas on how to incorporate Dwarves in your games of ASOBH. The rules for ASOBH are NOT included in Hammer and Forge, so the main rules are required to use anything out of this supplement.
The first part of Hammer and Forge is mainly to describe a certain part of Norindaal that pertains to Dwarves, much like the isolated area for Fightin' Fungi (the first official supplement for ASOBH). It starts out with a nicely colored map, then introduces you to the background behind various Dwarven communities. They also mention other creatures that inhabit this same region, including; hobgoblins, undead, possessed dwarves, and the obligatory dragons.
Then comes the heart of all SOBH games, the traits. Every character in your warband might have the same Quality and Combat, but the traits are what make them unique. You might think there is only so many things you can add to this simple game engine to make it different, but Hammer and Forge adds a whole new level. There are black powder weapons, drunken rules, dragonslaying, and even a battle giant (I think I need to make one of these!). Black powder is completely optional in your games, but included are some rules to add a little chaos, such as smoke tufts from gunfire that drift in the wind each turn. Later in the book is also rules on using cannons, awesome!
There's only a handful of new spells added in here as well as new group actions, but then brand new layers of customization are included in the form of Rune Magic, Magic Items/Beverages, and Feral Traits. Some of these new rules can be slightly more complicated than what you want in your games, however, I personally like how many new options are available. Nothing is mandatory in how you outfit your characters in your own games, use what you want.
Next up are scenarios, campaign rules, and profiles. There are only a handful of scenarios, but each is a flavorful story, aimed to be one-shot adventures in your campaigns. The profiles take up a good chunk of the book. From orcs and goblins to dragons to the various Dwarven societies of Norindaal, you shouldn't run out of ideas on making your own warbands from all the listed characters.
Lastly are a few pages of a Dwarven Dictionary and some catch phrases. Why do you need this? You probably don't. But Andrea Sfiligoi obviously has a well developed game world of Norindaal and is trying to input this wealth of background into these supplement books. It just adds flavor to all the gamey material.
Overall I enjoyed Hammer and Forge. If you are veteran player of ASOBH, I would recommend Hammer and Forge just to get all the new traits and abilities. If you are new to ASOBH, I would say hold off on Hammer and Forge until you have reached the point where you want to inject some new rules into the game.