The compilation of a set of collected works brings with it the problem of developing criteria for selection; what lines of thought are to be favoured or downplayed or deleted. For after thirty years or so of writing, the shape of ones thinking only really emerges fully with this advantage of hindsight. But this itself is to privilege the retrospective selection over the full developmental diversity of avenues of investigation. For in truth our studies go off in many directions – some prove fruitful, some rapidly become cul-de-sacs; some lie dormant and then accelerate rapidly, whilst others blossom early but then fade gradually. All of this only becomes clear later.