Well, yes, Robin Cook fell for the story, like so many others, but those who have studied the matter more deeply disagree. Take Jason Burke, for instance, a major contributor to the BBC documentary "The Power of Nightmares". In his book "Al Qaeda", he wrote the following:
It is often said that bin Ladin was funded by the CIA. This is not true, and indeed it would have been impossible given the structure of funding that General Zia ul-Haq, who had taken power in Pakistan in 1977, had set up. A condition of Zia's cooperation with the American plan to turn Afghanistan into the Soviets' 'Vietnam' was that all American funding to the Afghan resistance had to be channeled through the Pakistani government, which effectively meant the Afghan bureau of the Inter Services Intelligence (ISI), the military spy agency.
The American funding, which went exclusively to the Afghan mujahideen groups, not the Arab volunteers [bin Ladin's groups], was supplemented by Saudi government money and huge funds raised from mosques, non-governmental charitable institutions and private donors throughout the Islamic world. Most of the major Gulf-based charities operating today were founded at this time to raise money or channel government funds to the Afghans, civilians and fighters. In fact, as little as 25 per cent of the money for the Afghan jihad was actually supplied directly by states.
Page 59, Al Qaeda: The true story of radical Islam. Jason Burke
but we are moving rather far away from science here.