By Way of Deception is Victor Ostrovsky's memoir. Ostrovsky is the author and previous Mossad case officer, and the work is his reflection on his disillusionment with Israel's intelligence agency, called Mossad for short.

After working for Mossad for only four years as a katsa, a case officer, Ostrovsky resigned after being falsely blamed for a failed mission to capture officials of the Palestine Liberation Organization (PLO). In his book, Ostrovsky strives to expose the Mossad and its merciless methods of pursuing the enemy. His purpose is to show that the Mossad has become corrupt due to uncontrolled, excessive power.

In exposing the Mossad, he reveals many operations he learned about while working for the Mossad. One operation discussed was the aversion of Black September's assassination attempt on Israeli Prime Minister Golda Meir. A second operation discussed is Mossad's intentional interference in America's peace negotiations with Palestinians and Israelis.

Even Ostrovsky's story of his own personal involvement with Mossad exposes the institute's corruption. In 1977, after Ostrovsky was interviewed and psychologically and physically evaluated by Mossad, he was offered a job that would require a lot of travel, which he refused in favor of staying with his family. Later, he learned the job he was offered was that of assassin. In 1982, Ostrosky was recruited by Mossad again and offered the position of katsa, a position he took and held for four years before needing to resign. After resigning, he was commanded to fight in the front lines. Fearing for his life, he took his family and fled to Canada.