From the website:
The Red Waaagh! is a 112-page hardback book introducing the Sanctus Reach campaign. Inside you will find: Waaagh! Grukk, which is the story of the Red Waagh! and its attack upon Alaric Prime. There are twelve scenarios that allow you to refight the battles of the Red Waaagh! and five datesheets that provide detailed rules for famous formations that fought in the war for Alaric Prime.