I’m always on about the importance of having a clear business purpose – not necessarily the lofty do-good type that P&G, Unilever and co now seem to think they must have, just a reason why an enterprise exists, what it’s there for, in terms that its customers would recognise and value. This Harvard academic thinks so too, and makes the case brilliantly in this pithy book. It’s an accessible, human approach to business strategy development, with lots of examples and a how-to guide. Montgomery’s “purpose” is what I’d call a proposition, for the overall business rather than an individual product or service, and she shows how to use it to build an integrated business strategy. Her other big point is that a business strategy is not a static thing that can be declared complete, and it’s the leader’s job to keep challenging and evolving the strategy – hence the book’s title. The Gucci and Apple stories are great, too.