This book delves with the idea that super successful people are not a result of their innate greatness but a result of two factors - opportunity and cultural background. It shares stories of extremely successful men like Bill Gates, Bill Joy, Robert Oppenheimer, The Beatles and others and digs deeper to show that all these people had had an extraordinary opportunity which was not available to others at that point in time. So, there success cannot be attributed to their greatness but to their circumstances.
The book tries to debunk the "individualistic" model of success so popularized by the western media of the "self-made-man". Gladwell argues that there is no self-made-man and the success is a combination of the opportunities and culture (which includes the genes the person is born with).
The idea is not to demean the achievements of the super-successful people. It is not that they did not do anything. Obviously, to be a superlative success in anything, it takes a great deal of hard work and inherent talent. The only point Gladwell tries to make is that "luck" - for want of a better word - also plays a very crucial part in their success.
I would recommend this book. It gives a fresh perspective on success and its ingredients.