Books for intermediate/advanced investor?

[Justen Crews]

Hi, thanks in advance for feedback. 

I'm 38, have a good job, and own 12 single family investment homes.  Things are going great.   I've read dozens of books, and they all seem to be directed toward the novice or wannabe investor 

What books are there for the almost-millionaire?  Doesn't necessarily need to be about Real Estate.  I feel like now that I've gotten to this point in my Investing career, it's up to me to Lead myself.   

MONEY by TonyRobbins was the best book I've read recently.    I'm not trying to be "rich," I'm trying to build a secure future for me and my family.  As I say it, "I'm running as far away from failure as I can" 

Thanks!