Rob Arnott and his colleagues have, in The Fundamental Index, produced one of the most controversial books in years in the investment world. Barely any casual reader would ever realise it.

Fundamental indexing is a style of investing championed by Arnott and others, in which a fund buys all the stocks in an index, and weights them according to their economic scale on "fundamental" measures, such as sales, cash flow, book value and dividends. This differs from normal index investing, where holdings are weighted according to the value the market puts on a company.