Jeff Paul used to sell a book called "How You Can Make $4,000 A Day, Sitting At Your Kitchen Table, In Your Underwear!" Since 1996, he used full-page ads in business opportunity magazines and TV spots to sell this book, and over 90,000 copies have sold. The price used to be $29.95. A more comprehensive, back end product went for hundreds more, and included audio cassettes and more extensive information.
The book contains some interesting information, but at just 79 pages (over 20 of which is a sales letter for the full seminar), there isn't enough to get started with your own business, at least not confidently. However, you will get a lot of good , general ideas on how to sell information products using mail order. Since it's now offered free on the Internet, we recommend you read it for the ideas. After reviewing Jeff Paul's book, I believe the greatest hurdle in getting started with this business is 1) Researching and writing your information product and 2) Writing a sales letter that converts.
Speaking of sales letters, another Jeff Paul product you may want to consider is his ebook called "Killer Copywriting." This is a 200-page ebook that is generally well-regarded and is worth checking out if you are interested in honing your copywriting skills.