Zig Ziglar has been writing and speaking for several decades. One of his most well known books is called, "See You at the Top", which is also one of the very first self improvement books I've ever read. His most famous saying is, "You can have everything in life that you want if you just help enough people get what they want." He was one of the most enthusiastic speakers around. He had a fall a couple of years back and can no longer move around the stage like he used to but he still does speaking events. I saw him speak 10 years ago, moving around the stage, kneeling down on one knee to whisper a point, just full of energy. I also saw him speak after his fall recently and although he can mostly only speak from a sitting position, his passion and energy is still there. He is one of the most respected speakers in the business.