GDW even more than SPI and Avalon Hill could be all things to all gamers, from RPGs to board games to miniatures rules. Volley and Bayonet presents a shift away from the more fiddly and detailed tactical rules of the time towards something which in some sense is closer to a board game than one with miniatures.
The rules cover land warfare in the 18th and 19th century between massive armies. As such, the ultimate unit is the figure base representing roughly a brigade. The number of figures mounted on the base is meaningless though for 25mm, the recommended number is 10 through 12 with an appropriate label naming the unit. A person could if they wished mount as few or as many figures as they wish. The base size and label are really the most critical pieces of information.
Scale is also along the same lines with an inch = 100 yards. Each turn equals an hour of time. The goal is to allow players to game very large battles in a space around the size of a ping pong table.
The rules do not present the kind of competitive format as in WRG games. They are intended to simulate engagements rather than promote a contest of equals.
The rules are still in print. The quality of the rules shows an understanding of miniatures play that the authors achieved through experience. Of course, supplements abound.
An interesting and unusual supplement for the American Civil War, this slender book provides scenarios for battles in the eastern and western theaters. It includes a few smaller battles requiring a few bases of figures. A scenario will include a map of the terrain as well as a breakdown of the units available and the strength points assigned to them.
Additionally, there is a section in the back of the book which utilizes the GDW game A House Divided as the basis for a campaign game. Instructions are provided for transferring a battle from the game board to the table top using generic units from both North and South. The actual game board is included in a rather dull black and white so owning A House Divided is not a requirement to playing a campaign though the actual board game will look a lot nicer.