In his decades mentoring Silicon Valley's elite executives, Bill Campbell became the trusted confidant to tech leaders including Apple co-founder Steve Jobs, former executive chairman and CEO of Google Eric Schmidt and Facebook CEO Sheryl Sandberg.
Though the CEOs Campbell coached were high-profile, Campbell himself was more of a secret weapon. Schmidt, who met with Campbell "just about every week" for 15 years, says part of his brilliance was his trustworthiness.
"It became very clear that I could have conversations with him that I could not have with anyone else, in particular my own hopes and fears," Schmidt tells CNBC Make It. "And so once you have established that level of trust with a coach, then you are working together to solve problems."
Now Schmidt's book, "Trillion Dollar Coach: The Leadership Playbook of Silicon Valley's Bill Campbell" — written with two other Google executives — reveals the best bits of wisdom from the legendary executive advisor, who passed away at age 75 in 2016.
Campbell, who originally started his career as a college football coach, was dubbed the "trillion dollar coach" for the collective value of the companies with which he worked, though that figure might actually be conservative.
"I think it should be the $2 trillion coach if you add it all up now," Google billionaire Schmidt tells CNBC Make It. "And all of our interviews indicated that everyone agrees they would not have been nearly as successful without that coaching."
Here, co-authors Schmidt (also the former chairman of Google's parent company Alphabet), Jonathan Rosenberg (a former senior vice president at Google and an Alphabet advisor) and Alan Eagle (a communications director at Google) each share with CNBC Make It the single most important piece of advice they learned from working with and studying Campbell.