Now that our book, Why We Want You to Be Rich, is out, I can tell you what working with Donald Trump has been like.

Millions of people know "the Donald" as the tough guy who says, "You're fired" at the end of The Apprentice. I've been asked often if he's that gruff in real life. The answer is yes. My experience with Donald is that he's being real whether he's on camera or off. He never pretends to be Donald Trump. He is Donald Trump.

Obviously, co-authoring a book with him has been a milestone for me -- as an author and as a businessman. Appearing on Larry King Live, The Big Idea with Donny Deutsch, The Today Show, The Early Show, and CNBC with Donald gave me more credibility in the business world.

An Unofficial Apprenticeship

Yet I gained more than just recognition and credibility. I also became a better businessman and a better person just from working with Donald over the years.

Here are a few of the ways that knowing Donald has enriched my life:

1. I got tougher.

   I know many people don't like Donald because he comes across as a tough guy. That's their problem. In spending time with him, I realized that I wasn't as successful as I could be simply because I wasn't tough enough.

   As a businessman, I often didn't say what I wanted to say because I was afraid of hurting someone's feelings, or of having my feelings hurt. Instead of being forthright, I would be polite. Because of my association with Donald, I took back control of my business in 2005 and 2006 and fired people who should have been let go a long time ago.

   The employees I got rid of weren't bad people, they were just the wrong people for my company. Today, business is thriving and people are happier.

2. I became kinder and more respectful.

   One of my problems is that I'm very impatient and get angry too quickly. I believe Donald can be the same. Yet I saw him be patient, kind, and respectful in many situations that would have caused me to lose my patience.

   When I asked him about this trait, he simply said, "One of the most important lessons my parents taught me was to treat all people with respect, even if I'm angry with them." Today, in my dealings with people, I do my best to treat all people with respect -- especially if I'm angry at them. Although I haven't always been successful, I believe I've become a little kinder as a result.

3. I got richer.

   My wife, Kim, and I have more than enough money. We consider ourselves rich. When we entered Donald's world, however, we saw a whole new level of rich.

   There's a difference between being a millionaire and a billionaire. The Trump lifestyle -- the penthouse, mansion, limos, and 727 -- gave me a firsthand glimpse into his world, and I began to understand why he constantly talks about thinking big.

   Just being around him, I began to think bigger and richer. I set my sights on becoming a billionaire and began redesigning my business to become a billion-dollar business. Today, I constantly remind my staff that my job is to make them millionaires -- and their job is to make me a billionaire.

4. I became less petty.

   One day, during a meeting in Donald's office, I was complaining about someone we were doing business with. I didn't like the way we were being treated. When I asked Donald about this person and voiced my concerns, he simply said, "Don't be so petty. Sometimes you have to do business with people you don't like. It doesn't mean you have to be like them or like them."

   From that, I learned to think bigger and, more important, to know the difference between paying attention to details and being petty.

5. I was reminded of the value of collaboration and partnership, as well as the value of loyalty.

   I saw this repeatedly as we developed the concept for our book, discovered our shared concerns and our passion for teaching, and shared the stage for dozens of media interviews.

   Getting on Larry King Live and The Today Show is easy for Donald, but in booking a few of these interviews he insisted that we get equal billing. And when a show host mispronounced my name, Donald jumped in to correct him on national television. These simple acts spoke volumes.

History in the Making

About the same time our book was released, a new book about Andrew Carnegie, the richest man in the world at the start of the 20th century, was also published. The timing is ironic. I believe that when history looks back at the start of the 21st century, Bill Gates, Warren Buffett, and Donald Trump will be seen as the Carnegies of the era.

Many historians view Carnegie as a ruthless man, and I know that many people also see these three in the same light. Yet if you study Carnegie's life, you find that he was extremely generous, and donated billions of dollars in support of building libraries and preserving world peace.

He even envisioned the League of Peace, a precursor to President Wilson's League of Nations. I trust that history will allow a space for the good that Gates, Buffett, and Trump have done, and not simply resent them for their wealth.

Donald and I got together to write our book as teachers, not just as rich men. We're both concerned about the lack of financial education in our schools. In the process of writing it, I not only became a richer person, I believe I also become a better human being. And for this, I feel privileged to have seen a side of Donald Trump that not many people see.