Book publishing in the 20th century has largely been the story of Self-Help. In the last two decades, the industry has expanded continues to grow at an accelerating rate. In many publishing houses, it is the money from the self-help division that allows other genres even to exist.

In the last episode of the series, Robin Ince looks at the trends in self-help that took it away from soulful wellbeing towards business and the arts of making money.

Dale Carnegie wrote "How to Make Friends and Influence people" in 1936. In the Carnegie model, the book is just one part of a wider programme of courses and seminars, all aimed at giving participants the tools they need to succeed in corporate and commercial life. It all costs money.

As Oliver Burkeman points out, this has become the business model for the modern Self-Help guru. The book acts like a calling-card, establishes the author's credentials; the weekend conference puts the reader in contact with the author, and the people with clip-boards waiting outside the auditorium will gladly take your credit card number to ensure you get the insights you then know you need.

Jessica Lamb-Shapiro even found herself at a motivational conference for those interested in writing their own self-help books.

Many of the biggest selling books of the century have something in common: "Positive Thinking". Even worse for the sceptically inclined, they invoke something referred to as the "law of attraction".

As the Self-Help market - described as a by-product of really advanced capitalism by Micki McGee - continues to expand into newer and bigger markets, a way of sorting useful Self-Help literature from the less useful, even harmful, magic-thinking is arguably more important than ever. Show less