Reavers of Harkenwold is a 4th edition Dungeons & Dragons adventure in two parts which comes with the Dungeon Master's Kit. Basically it *is* the Dungeon Master's Kit, if you already have a Dungeon Master's Guide and don't need the streamlined paperback version of it. In spite of that paperback you might not need, the Kit is still good value, because it comes not only with the adventure in two booklets and three double-sided maps, but also with all the tokens you would need to run the game, player characters as well as all monsters. This product very much appears to be designed to be played "right out of the box". The catch is that it isn't quite that easy to do that.

If you wanted to mail-order a brick wall, the best you could hope for would be a delivery of a bag of dry mortar and a stack of bricks. You'd still need to add your own ingredients (water), and have some knowledge and skill in mixing the water with the mortar, bricklaying, and the proper proportion of mortar to bricks. Reavers of Harkenwold is pretty much the same thing. It has about 20 pages of adventure outline, places of interest, and NPCs (the mortar), and about 40 pages of combat encounters (the bricks). You still need to add your own ingredients (the roleplaying), and have some knowledge and skill to put it all together into a sturdy whole. Run by an experienced DM, Reavers of Harkenwold can be an excellent adventure. But I'm not sure it is the easiest adventure to run for a new DM who only got the D&D Essentials red box and tries to run this as his second adventure ever.

Reavers of Harkenwold is designed to take a group of players (preferably 5 or even 6 of them) from level 2 to level 4 in about 20 combat encounters interspersed with some roleplaying. How long that will take will depend on how much roleplaying the DM and the players like, but if you count about 2 combats per session you'd end up with about 10 sessions, which is a lot of adventure. The combat encounters start out easy, but then get harder, even taking into account that the players will gain a level in the middle. Careful! The adventure does not tell you how to scale the encounters down in difficulty, or in fact that they are designed for 5 players. If you try them with just 3 players, or even 4 very new players, you might end up with a total party kill (TPK).

The combat encounters are mostly quite well done. They use a good mix of opponents, sometimes putting enemies the group fought before together with new ones, which is a good design. It mixes the surprise of monsters with new abilities with the recognition of old foes. Some of the maps are also re-used several times, with one generic farm map serving to represent 4 different locations, which is maybe overdone. If you have other maps available, you can probably switch that one out in a battle or two.

The biggest flaw of the Reavers of Harkenwold adventure on the map side is that there are no maps at all for the last 4 battles, the grand finale, which plays in the right half of a keep. Even weirder, there is a rather excellent map of the left half of that keep, which is only used for one battle. You will have to get the missing map as jpegs somewhere online (for example here), or if you are subscribed to D&D Insider from the official site. Or create them yourself with some map-drawing software like Campaign Cartographer / Dungeon Designer. Or you use some dry erase map or dungeon tiles. In any case you'll end up with a style break when moving from one half of the castle to the other. Unless of course you have far too much time on your hand and decide to build the whole castle in 3D. [EDIT: Since I wrote this, I made some maps of my own.]

The biggest selling point of the Reavers of Harkenwold is it's open structure. There is some flexibility: Some encounters can be skipped, or played in a different order. Skipping or failing too many encounters will make the end of the adventure harder, if not impossible. That isn't a bad thing if played right, as it teaches the players that their actions have consequences and they can't just rush through and be confident to still be rewarded. As I said before, with some good DMing, Reavers of Harkenwold could be one of the best adventures for 4th edition. But it does require some preparation, an added dose of roleplaying, and creating of the missing maps. If run as a linear series of combat encounters with little or nothing in between, the quality goes way down, but would in most cases still somehow work. Just be aware that with lower number of players or the players rushing directly to the end there is a good chance to wipe the party.