In several of the Jack Ryan novels (notably Hunt for Red October and Patriot Games) Admiral James Greer was the Deputy Director of Intelligence in the CIA. He had a taste for coffee, and was never seen without a cup of it, having a coffee machine in his office.
He suggested his first submarine to play the role of the Red October in the deception that ultimately allowed the US to keep possession of the submarine following Captain Marko Ramius' defection.
Greer dies from pancreatic cancer during Clear and Present Danger.
In the novels, Patriot Games was a prequel to The Hunt for Red October; however, the chronology of the movies was altered for The Sum of All Fears. While the novel takes place after Clear and Present Danger, the film takes place earlier in Ryan's career and how he met Greer.
The Sum of All Fears was not part of the Alec Baldwin/Harrison Ford trilogy, but rather an intended reboot of the franchise. The discrepancy can be seen in the fact that he met John Clark for the first time in Clear and Present Danger and the Clark character was significantly different; Ryan is also married in the first three films. Greer didn't appear in the film, with the exception of William Cabot.