He paints a portrait of a rogue agency which devoted more time to covert action to oust governments than to gathering information about America's enemies, and which failed to predict every big international event from the outbreak of the Korean War to the fall of the Berlin Wall and the 9/11 attacks.
The book, Legacy of Ashes, has infuriated some former CIA officers who insist that the agency needs support, not denigration. One dismissed Weiner's criticisms as "superficial and unfair".
It details how the CIA relied from the outset on low-level sources and ill-trained officers. In 1953 it sent its first officer to Moscow, but he was so inept that he was seduced by his Russian housemaid - really a KGB colonel - photographed in flagrante and blackmailed.
In eastern Europe in the early days of the Cold War, almost every agent parachuted in was captured and killed. More than $1 million was sent to a fake spy ring set up by Polish intelligence - effectively paying money directly to their enemy.
During the Korean War, none of the CIA's 200 officers in the South Korean capital, Seoul, spoke Korean. In 1952, the CIA station chief concluded that nearly every Korean agent either "invented his reports or worked in secret for the communists".
Things were little better in the battle with America's main Cold War foe, Weiner argues. An internal CIA report in 1956 found that just two of the 20 spies recruited in the Soviet Union had any contact with the government or military. One of its top sources was a Russian vet.
When the Berlin Wall was erected in 1961, among the CIA's best agents in East Berlin were a newspaper salesman and a roofer, who occasionally worked in the Soviet military compound. Small wonder, Weiner argues, that the CIA concluded that Russia would have 500 intercontinental ballistic missiles "ready to strike" them that year, when the true figure was four.
For eight years after 1986 the CIA sent reports to Presidents Reagan, Bush and Clinton on the strength of the Soviet military which they knew came largely from sources controlled by Moscow.
The CIA's current difficulties in the Middle East are part of a long and undistinguished history. When Iraq invaded Kuwait in 1990, Robert Gates, then the agency's head and now the American defence secretary, was at a family picnic. A friend of his wife asked him: "What are you doing here?" Mr Gates said: "What are you talking about?" She replied: "The invasion." Mr Gates responded: "What invasion?"
Weiner concludes that even the CIA's apparent successes in covert action proved to be strategic failures. Ousting the Iranian government in 1953 led inexorably to the revolution of 1979. The CIA backed the 1963 Ba'ath Party coup in Iraq which opened the door for Saddam Hussein.
It's not clear that Tim Weiner is the most objective source for national security news, but the failings of the CIA are plain to see in the sheer number and magnitude of their mischaracterizations and miscalculations over the years regarding America's adversaries. This could be a very interesting read.