Deceivers' Orders is a three-part tome found in Act II of Diablo III. It is found on the corpses of Envoys of Belial in various locations. They form part of the Eavesdropper achievement.
The parts read as follows:
Part I (Sewers of Caldeum)[]
My exemplary servants, Keep the witch alive until she talks. Pain will loose her tongue, but only to a point. Remember what happened with the vizier's assistant...? It was a pleasurable time, I admit, but the man had only incoherent babble and bloody strands of pus spilling from his lips by the end. — Belial
Part II (Dahlgur Oasis)[]
Overwhelm the enemy and seize his/her companions. There is a witch among them and... another... a girl. Bring them to me along with the Black Soulstone. They will be searching for the head of Zoltun Kulle. Scour the oasis for it. Some old sorcery lingers on the skull, and it must be mine. — Belial
Part III (Desolate Sands)[]
Miserable wretches, I have no time for your excuses. Caldeum is on the brink of rebellion, and the enemy is closing in on the archives of Zoltun Kulle. Slaughter him/her and bring me the mad wizard's head and the Black Soulstone, or I shall inflict incomprehensible agony upon the lot of you. — Belial