How do I become a full-time writer?

Here's what Ray shared:

I started working as a software developer straight out of college, and watched from the sidelines during the PC boom, as computer books flooded the market. I kept telling myself, "I can do that. Heck, I can do much better than that!" But I never found the time.

At one of my jobs, our group's tech writer quit just prior to a release. To his credit, he honestly thought his job was done and the documentation was ready. I had recently joined the group and read the documentation closely--just so I could get up to speed on the group's software.

I found numerous errors. The tech writing department had no one to spare, so I volunteered to fix the documentation, which essentially meant rewriting almost from scratch. I still remember the dread in the editor's eyes when she first met me. I could tell she was horrified at the very notion of a software engineer writing documentation.

Many years later, out of the blue, I got fed up with the corporate rat race and decided to quit. Then I had to figure out what to do with myself. I picked up Borland's Delphi, which was brand new, and thought I might write some Windows shareware. I started participating in newsgroups, answering questions about Delphi. Several beginners' books had come out, but no advanced books. I saw an opportunity for an advanced Delphi book, and submitted a proposal to the Waite Group. They were interested, but wanted some changes. I obliged and resubmitted. This went back and forth several times and eventually they sent me a contract.

They wanted to bring in a coauthor because this was my first book, and asked me to partition the book into my chapters and his chapters, which I did. I completed my chapters on schedule, but they had no yet found a suitable coauthor, so I finished the rest of the book on my own. Macmillan bought the Waite Group while I was writing the book, and they cancelled it soon after--just when it was starting to gain popularity.

About that time I learned about this email list and joined. I discovered that the terms in my first contract were abysmal, so I found an agent to help with future books. Since then, I've written another half-dozen books or so (including Shakespeare for Dummies). I've taken on some part-time teaching, training, and consulting work, but I consider myself a full time author.

In my best year, I earned about half what I had earned as a software developer, but I greatly enjoy the freedom. The year after my best year, I developed rheumatoid arthritis, and I have never been that productive since. My wife now pays most of the bills (she finished her Ph.D. in physics and now has a real job, poor girl), but my pittance helps. Now that I'm getting Remicade (one of the latest and greatest, and most expensive treatments for RA), I am able to write more, and I expect to finish a book this year. I haven't written a single article since I developed RA, but this year I expect to start writing articles again. But first, I have this book to finish...

My thanks to Ray Lischner, author of C++ in a Nutshell, for permission to republish this question.