Here is a fascinating insightinto a market that's experienced creative destruction: the market for books. However, you might be unaware that the market has been altered to such a degree that physical copies are now, in many instances, cheaper than e-books.

This stems from a number of factors - not least the nature of the market for the latter, where "the shift in ebook pricing reflects a change in the contractual terms agreed between Amazon, which controls up to 90% of the UK ebook market, and the major publishing houses", and thus there's the suggestion that Amazon have considerable market power in relation to both producers and consumers.

Lots of interesting economics, not least the issue of substitutability and complementarity, and costs - how can an ebook be more expensive than a physical copy, given their comparative cost differences.