From the introduction:
The Complete Red Book of Spell Strategy is a collection of new class options, Feats, Backgrounds, Rituals, Spells, Magic Items, Monsters, and race.
There is a focus in this work on the Eastern Realms (particularly Thay and Rashemen and its surrounding underdark), but the majority of the rules are written for use anywhere in the Forgotten Realms.
Document includes new feats, archetypes, spells, etc. Two versions of this product were published in rapid succession - The Red Book of Spell Strategy and three months later The Complete Red Book of Spell Strategy. The latter version contains everything in the former version plus additions and is preferred.