Gears of War: Judgment is a prequel that takes place just after the first Locust attack, so you shouldn't need any prior knowledge of the series to get a hang of the proceedings. If you have gaps in your Gears knowledge, though, one retailer is making it a bit easier to fill in the blank spaces.

Epic Games announced that Walmart pre-orders will get a choice of Gears of War 2 or Gears of War 3 with their pre-orders. This is in addition to the first run of Judgment discs including a download of the original game, so you could buy Judgment and get 75% of the Gears franchise all in one go.