Rich Dad, Poor Dad by Robert T. Kiyosaki

When I was about 19, this book changed my entire outlook on money and finances. Looking back, and reading through the book now, I see a lot that I disagree with, but it sparked my thinking about how to manage money, and what financial freedom truly means. Not a practical book, but definitely a good start if you have no “financial motivation.”
The Millionaire Next Door by Thomas J. Stanley

This book, which I read recently, is the result of years of research of America’s millionaires: how they live, what they wear, what cars they drive, how they made their money, etc. It was definitely inspiring to me, and also got me thinking about the impact of wealth on future generations, both good and bad.

Cashflow Quadrant by Robert T. Kiyosaki

This book builds on Rich Dad, Poor Dad and goes into detail about how to build multiple streams of income and gradually reduce your reliance on earned income. It contains overviews of the impact on personal finances and income of things like real estate investment, entrepreneurship, and investing in businesses.
The Richest Man in Babylon by George S. Clason

This is a deceptively simple book that contains a series of financial parables that teach the importance of always saving, the power of compound interest, investment, insurance, and other time-tested financial truths. Easy read and a good reminder of some very basic lessons. Again, good to read if you find yourself lacking that “financial motivation.”