This book presumes that just because you're smart and capable, this doesn't mean you'll be any good at running a business. Jumping straight in with the numbers, it immediately shows that figures are everything - don't understand the numbers, and you are going to fail.
However, from there the book goes on to be an educative primer on just about every aspect of owning and running a small business - from closing the right types of sales to identifying your core competencies; from spreading your client base to dealing with banks, venture capitalists and other lenders.
There is basic advice on building a business for sale; how to treat competitors; negotiation skills; holding on to clients; choosing salespeople; and who to turn to for advice.
In 274 pages it isn't going to teach you all you need to know about the above, but with lots of real-life cases from the author's mentoring background and own business (and in the form of letters, presumably from his magazine column, which are too brief and don't add much), this book is a fast and useful read containing many pieces of advice that I suspect will serve any budding entrepreneur well.