Influence: The Psychology of Persuasion

I think more than software sales it's useful to learn about "sales" and "persuasion". I've found Robert Cialdini's Influence to be a great read!

In addition to the classics of cognitive psychology (Kahneman, Taleb, et al.), I would also recommend books on psychological manipulation, religious cults, and con men. The following books offer a multi-disciplinary perspective on psychological techniques to improve awareness and exploit other people, both of which are essential to enhance your perception and protect yourself against fraud and manipulation. Cialdini, Robert (2006) Influence: The Psychology of Persuasion Guinn, Jeff (2017) Road to Jonestown: Jim Jones and the Peoples Temple Ekman, Paul (2007) Emotions Revealed: Recognizing Faces and Feelings to Improve Communication and Emotional Life Kahneman, Daniel (2011) Thinking, Fast and Slow Mitnick, Kevin and William Simon (2002) Art of Deception Navarro and Karlins (2008) What Every Body is Saying: Ex-FBI Agent's Guide to Speed-Reading People Nietzsche, Friedrich (1887) On the Genealogy of Morals Rhodes, Richard (1986) Making of the Atomic Bomb Sun Tzu (c. 400 BCE) Art of War Taleb, Nassim Nicholas (2005) Fooled by Randomness Wright, Lawrence (2013) Going Clear: Scientology, Hollywood and the Prison of Belief

I have to strongly second this: one of the best psychology books around.

"Influence," by Robert Cialdini - although it's not necessarily packaged as a marketing book.