more important (for instance, as emphasized by the title of Strong’s review, dispersal rather than aggregative behaviour), but rather on understanding those broad categories of life histories for which one or other of a range of mechanisms may be responsible for long-term persistence of both hosts and parasitoids6r19--21. For example, although some hosts and parasitoids (especially univoltine species) do indeed redistribute themselves among patches in each generation, others show less complete mixing, with many of the hosts and parasitoids tending to remain within the patch from which they originated. Scale insects, for instance, develop colonies over several generations, with only a fraction of progeny dispersing in each generation. In such cases, t imes of transit of hosts and parasitoids among patches and the accidents of dispersal seem likely to be more important than patterns of parasitoid aggregation within any one patch6,**. It is not that one kind of factor is of dominant importance, nor yet that each system is ineluctably unique; we see the way forward as relating different categories of dynamical factors to different broad categories of life histories. We end on a broader note. Like several of his earlier reviews, Strong’s account of the history of parasitoid theory is reminiscent of ‘1066 And All That’. Ideas develop in a neat, linear way, and the cast of characters hold clearly defined views. Reality is more complicated, with most of the progression of scientific ideas occurring in a convoluted, higgledy-piggledy fashion. Gould*3 has several t imes made this point in a compell ing way. For instance, what he calls ‘cardboard history’ gives us the WilberforceHuxley debate as a stirring rout of the forces of darkness by the forces of light; the reality, it would appear, was more equivocal, with a good deal of scientific reasonableness on Wilberforce’s side. We are all better served by acknowledging these complexities, and by seeing our shared enterprise as one in which new ideas and new experiments build constructively on older ones, rather than as some bourse in which Good ideas displace Bad ones in linear sequence.