The biggest lie that comes to my mind has to do with Kisevalter's patently false recounting, in 1964, of what Nosenko had (or had not) told Bagley and himself in Geneva in 1962 about Penkovsky's "dead drop" in Moscow -- specifically, how and when (Dec.1960 versus Dec.1961) it was implausibly "discovered" and "monitored" by the KGB when a mysterious person (Kisevalter?) called a CIA officer's house on Christmas Eve and blew three times into the phone, pretending to be Penkovsky by giving the tightly-held prearranged coded request for an emergency check by CIA of his dead drop.
It's a complicated story, and I'll be getting into it shortly, but the bottom line is that Kisevalter, by denying that Nosenko had said certain (tape recorded) things in Geneva in 1962, was obviously "covering" for the telltale gaps and mistakes in the under prepared "legend" of false-defector Nosenko.
-- MWT 
PS Bagley writes about what really happened in chapter 14, Dead Drop.
Now for the "nuts and bolts" of The Penkovsky Dead Drop incident, and the reason Nosenko, in 1964, needed
George Kisevalter to cover up / obfuscate / lie about one of the mistakes Nosenko had made in his 1962 "recounting" of it.
First, from "Spy Wars," here's what Nosenko told Bagley and Kisevalter in Geneva in 1962 (slightly paraphrased):
Bagley: "In 1962 Nosenko told CIA that the KGB's
late 1960 watch over American Embassy security officer in Moscow, John Abidian was so important ("We were trying to catch another Popov") that it called for Nosenko's personal supervision as deputy head of KGB's American Embassy section, but, unfortunately, it was
a big flop in that all that was found was an American girl's panties left behind in his bedroom.
"In 1964 Nosenko told a wildly different story.
Without referring to anything he had or had not said in 1962, Nosenko recounted the
great success of that KGB surveillance. According to Nosenko, in late 1960, they had spotted Abidian 'setting' up a dead drop for CIA on Puskin Street. The KGB had set a watch over the site, and week after week for at least three months the watchers' reports came across Nosenko's desk -- always negative.
"We [in CIA's Soviet Russia Division's counterintelligence section] could find no innocent explanation for this startling contrast. When meeting with Kisevalter and myself in tape-recorded sessions in Geneva in June 1962, Nosenko was supposedly becoming our agent and knew that any KGB detection of CIA work in Moscow -- regardless of its importance to his new CIA friends -- could affect
his own future security. He could not have failed to mention this "discovery," infinitely more significant than a girl's panties.
"We knew about that dead drop -- CIA had had only one, ever, on Pushkin Street. And neither Abidian nor anyone working with CIA "set up" that drop. Oleg Penkovsky did. At no time in 1960 or earlier had Abidian or anyone else from the Western side approached that building, much less entered its lobby, where, behind a radiator, the drop site was located. There was no reason to do so and CIA was careful
not to go near it. Even in mid-1961, when CIA wanted to confirm to Penkovsky in Paris that it could safely service the drop, Abidian was asked only to look over the general area to see whether or not he could eventually go to that address without moving outside the normal pattern of his daily life. He walked past but did not enter the building, and saw that it would be easy. Not only was his regular barber on the next side street, but on that corner was a bookstore where he sometimes browsed -- a bookstore with entrances onto both streets.
"The first time Abidian actually stepped inside the apartment building to check that drop site occurred at the end of December, just as Nosenko had said --
BUT OF DECEMBER 1961, NOT 1960.
"Crash! went Nosenko's career story. He claimed to have finished his service in the KGB's American Department at the end of 1961, only a few days after Abidian first went to the drop, so he could not have received reports of a stakeout over the weeks and months that followed.
"Even more startling was the
reason Abidian went there in December of 1961, which Nosenko evidently dod not know. Someone had triggered Penkovsky's signal arrangement -- and it was not Penkovsky." [see below]
...
Some much-needed background:
GRU Colonel Oleg Penkovsky defected to the U.S and Britain in London in April, 1961, and met with his four handlers (two CIA --
one of whom was George Kisevalter -- and two MI-6) several times in London and in Paris before he eventually returned to Moscow for good in early October 1961, from there continued to spy for CIA and MI-6 for ten months (most famously during the Cuban Missile Crisis) at the end of which time he was arrested, "tried" for treason, and executed.
Early on during the first two weeks of meetings, Penkovsky and his four handlers had agreed that he would set up a "dead drop" for himself in Moscow, and that if he needed a CIA agent to clear it of any messages, Penkovsky was to call one of two numbers in Moscow (twice, a minute apart) and, without saying anything either time, blow into the phone three times on the second call and hang up.
"Around 9 p.m. on Christmas Eve, 1961, the wife of the American Embassy's Assistant Military Attache, Alexis Davison, received two voiceless phone calls in succession. She could not hear any blowing into the phone, and she counted three minutes between calls instead of one, but it coincided closely enough with the planned signal that she decided to pass the word to CIA's chief of station, Paul Garbler, who was at a Christmas party at the ambassador's residence. When he got the message, he and Embassy security officer John Abidian left the party, and drove to a certain telephone pole to see if it had a chalk mark on it which would signify that the dead drop had a message fro Penkovsky in it which the CIA should retrieve ASAP.
Bagley: "The CIA file account states that no mark was visible, but in fact [Abidian later told me that] Garbler told Abidian that although he had not seen any mark, he could not be absolutely sure in the dark. So he asked Abidian to check the dead drop [in the lobby of an apartment building] just in case. Strangely, Garbler (whom Angleton later thought might be a mole) later told investigative reporter Joseph J. Trento in
The Secret History of the CIA, incorrectly, that there had been no mark on the pole and that he had opposed sending anyone to the drop."
"A couple of days later, Abidian checked on the (empty) drop behind a radiator heater in the apartment building's lobby in such a way that precluded the KGB, which followed him in a car to a bookstore near the drop, from seeing him do it.
"It must have been the KGB -- who else? -- who triggered the visit by using Penkovsky's signal system. Voiceless calls were rare; any voiceless calls coming coincidentally to this particular phone number were as unlikely as being struck by lightning, and two such calls in quick succession left no reasonable doubt. Sinister questions loomed. First, how could the KGB have known the signaling system? Probably not ten people in the world knew about it ...
(note:
George Kisevalter was one of them)
"... And how did the KGB know (as Nosenko's story revealed) that it was Abidian who went there?"
