Throughout the book, Ostrovsky claims to reveal details of the internal workings of the Mossad itself. Ostrovsky claims that Mossad has access to Jewish helpers all around the world called sayanim (sg. sayan). Their services can supposedly be requested on short notice and no questions are asked. Because of this, Mossad only needs 30-40 active case officers at any given time. He also explains the different departments functions and how liaisons are conducted with foreign intelligence agencies.
As he progresses as a katsa, Ostrovsky experiences growing disillusionment with the organization and its leaders, and begins to question its motives. This culminates in his retirement from the Mossad after being scapegoated for a failed attempt at capturing top PLO officials.
The title of the book is a translation of what Ostrovsky alleges is the former Mossad motto: be-tahbūlōt ta`aseh lekhā milkhamāh (Hebrew: בתחבולות תעשה לך מלחמה, "For by wise counsel thou shalt make thy war: and in multitude of counsellors there is safety." – Proverbs 24:6) where deception stands for wise counsel.
In 1990 Israel tried to stop the sale of the book, by the means of a preliminary injunction. This was the first time that a sovereign state tried to stop a book publication in another sovereign state. However this claim was rejected by courts in the United States.