One of the paradoxes of general practice is that we emphasize on the one hand how important it is that the general practitioner learns to tolerate uncertainty, and then regret on the other hand that so few general practitioners research the uncertainties they find in their every day work. In the first chapter of my first edition of this book I suggested that general practitioners were missing opportunities to take part in a fascinating and rewarding professional activity because of an unnecessary fear of the unknown, and tried to encourage more to try research for themselves. There has been...