WASHINGTON — In what amounts to a fight over who gets to write the history of the Sept. 11 attacks and their aftermath, the Central Intelligence Agency is demanding extensive cuts from the memoir of a former F.B.I. agent who spent years near the center of the battle against Al Qaeda.

The agent, Ali H. Soufan, argues in the book that the C.I.A. missed a chance to derail the 2001 plot by withholding from the F.B.I. information about two future 9/11 hijackers living in San Diego, according to several people who have read the manuscript. And he gives a detailed, firsthand account of the C.I.A.’s move toward brutal treatment in its interrogations, saying the harsh methods used on the agency’s first important captive, Abu Zubaydah, were unnecessary and counterproductive.

Neither critique of the C.I.A. is new. In fact, some of the information that the agency argues is classified, according to two people who have seen the correspondence between the F.B.I. and C.I.A., has previously been disclosed in open Congressional hearings, the report of the national commission on 9/11 and even the 2007 memoir of George J. Tenet, the former C.I.A. director.

Mr. Soufan, an Arabic-speaking counterterrorism agent who played a central role in most major terrorism investigations between 1997 and 2005, has told colleagues he believes the cuts are intended not to protect national security but to prevent him from recounting episodes that in his view reflect badly on the C.I.A.