Leaders at the top of al Qaeda's hierarchy, the evidence shows, completed plans and obtained the materials required to manufacture two biological toxins - botulinum and salmonella - and the chemical poison cyanide.

Al Qaeda is closely aligned with the Chechens.

There is evidence that some of al Qaeda's nuclear efforts over the years met with swindles and false leads.

Searches of al Qaeda sites in Afghanistan, undertaken since American-backed forces took control there, are not known to have turned up a significant cache of nuclear materials.

Among all the upheavals of war with al Qaeda, the surest indicator of the historic stakes is the ongoing rotation of top U.S. government managers - scores at a time - into a bunker deep underground and far from Washington.

Counterterrorism analysts have known for years that al Qaeda prepares for attacks with elaborate 'targeting packages' of photographs and notes.