David Weber and Steve White collaborated on four novels that were based on Task Force Games' STARFIRE boardgame series created in 1979 (now currently published by Starfire Design Studio). They are, in publication order, Insurrection (1990), Crusade (1992), In Death Ground (1997), and The Shiva Option (2002). Several years later, the stories were re-released in the correct chronological order of events, published as two omnibus editions: The Stars At War (2004 - Crusade and In Death Ground), and The Stars At War II (2005 - The Shiva Option and Insurrection). Two follow-up novels, Exodus (2006 - Steve White and Shirley Meier) and Extremis (2011 - Steven White and Charles E. Gannon), missed the boat entirely IMHO.
Taken from Wkipedia, these are the four major reaces involved in the novels:
Arachnid Omnivoracity - As the name implies, the Omnivoracity was made up of large creatures with a resemblance to spiders. While the Arachnids were intelligent, communication with them was found to be completely impossible. As a result, little is known about them other than the fact that they were quite advanced, and considered all other intelligent races to be food sources (and, in fact, treated captured subject populations much the way a herder treats sheep or cows). The first encounter between Terran Federation and Arachnid vessels led to Interstellar War 4. The attitude of the Arachnids toward other races made peace impossible, and all known Arachnid worlds were destroyed by bombardment from space by the combined fleets of the Alliance - save one small colony hidden, isolated from its homeworld by a hidden warp point. Interstellar War 4 and the fate of the Arachnids is described in the novels In Death Ground and The Shiva Option.
Khanate of Orion - A race of humanoid felines that believes strongly in honor and fighting, the Khanate was the first empire encountered by the Terran Federation. The Khanate and the Federation clashed during Interstellar Wars 1 and 2, but new leadership and a common enemy during Interstellar War 3 brought the two enemies together as allies. They have remained on good terms since that time.
Terran Federation - The Terran Federation is composed of humans from Earth. The Federation enforces a strict non-interventionist policy in the affairs of pre-starflight races within its borders, and as a result, humans are the only race represented by the Federation. The Federation has fought one civil war, as detailed in the novel Insurrection.
Thebans - An alien race from the other side of an unexplored warp point near the Federation/Khanate border. Due to an odd confluence of events, the Thebans worshiped the planet Earth as "Holy Terra", and claimed to be Terrans. They embarked on a vicious campaign to "free" humanity and "return" them to the worship of Holy Terra. Despite initial Theban successes, the Federation ultimately prevailed. The peace treaty following the war invoked severe limits on the Thebans, and prohibited them from building their own starships. Details on the Theban War can be found in the novel Crusade.