One CIA document offers a profile of Castro: It calls him intelligent but "not very stable" and "touchy, impatient and rash."
Another outlines plans to assassinate Castro, including a 1964 plan with connections to the Mafia. The mob and "patriotic Cuban exiles" eventually settled on a payment of $100,000 for assassinating Castro, $20,000 for his brother Raul and $20,000 for revolutionary Ernesto "Che" Guevara, plus $2,500 for expenses.
Another prominent thread throughout the documents is the 13-day crisis over Soviet missiles in Cuba.
On one white page from a meeting on Oct. 16, 1962, the first day of the crisis, Kennedy wrote out two columns: proponents of a blockade against Cuba and supporters of a military strike.
"It's interesting to see in his handwriting who's on which side," Dobbs said.
The blockade won out.
The materials are available online and at the Boston library. Some are still classified and aren't available.
The documents' release is important to historians, said University of Maine history professor Nathan Godfried.
"This is the raw materials we use in order to reconstruct the past," he said. "The more documents from different perspectives give us a clearer sense of what happened."