From the back of the book:
"On 1 May 3052, the largest single engagement of forces in the history of 'Mech warfare began. Twelve armies of ComStar's Com Guards clashed with twenty-five Galaxies of Clan forces on the hills and plains of the planet Tukayyid. The prize for this battle was the glittering blue gem of the Inner Sphere, the home of humanity: Terra.
A combination of Com Guard ingenuity, Clan short-sightedness, and plain luck allowed the ComStar forces to defeat the Clans one by one - only Clans Ghost Bear and Wolf managed to win any sort of victory. At the end of twenty-one days of fighting, both forces counted ComStar the victor; Earth was saved.
Tukayyid gives players the chance to change history. More than 25 scenarios represent all the major engagements of the battle of Tukayyid. As the Clans, players may engage in batchall, or bidding, to determine who among them is worthy to lead their forces to the victory that was historically denied them. As the Com Guards, the players must use superior numbers and guerrilla tactics to overcome the Clan's advantage of technology and skill.
Tukayyid is a BattleTech scenario pack that provides historical notes and personal accounts of this epic battle and features a unique point system that allows players to design balanced games and use the Clan bidding system."