lessons learned from Cuban Missile Crisis?

what lessons are learned from Cuban Missile Crisis?
Your sources are (Essence of Decision-Making: Explaining the Cuban Missile Crisis, Graham Allison and Philip Zelikow, 1999, Longman, ISBN-13: 978-0321013491) and Thirteen Days Movie { this is the link for the information about the movie – https://en.wikipedia.org/wiki/Thirteen_Days_(film) }