Influence: The Psychology of Persuasion
Book
A book by Robert Cialdini, highly recommended for understanding universal principles of persuasion relevant to negotiation, especially the concept of reciprocity.
Mentioned in 2 videos
Videos Mentioning Influence: The Psychology of Persuasion

The tactical playbook for getting 20-40% more comp (without sounding greedy) | Jacob Warwick
Lenny's Podcast
A book by Robert Cialdini, highly recommended for understanding universal principles of persuasion relevant to negotiation, especially the concept of reciprocity.

Tools of Titans with Brené Brown | The Tim Ferriss Show (Podcast)
Tim Ferriss
Robert Cialdini's book on persuasion, mentioned as a favorite among interviewees in Tools of Titans.