Funny things, seedlings. Everyone seems to agree how important they are, but at the same time no-one seems particularly keen on them as an actual focus of scientific study. Hence this book, which cites over 100 pages of references, rather few of which are directly concerned with seedlings. Similarly, many of the chapters; Eriksson and Ehrlén's chapter on seedling recruitment and population ecology is excellent, but would have been equally at home in a book on seed biology, population biology or general plant ecology. Eriksson and Ehrlén are concerned with the question: what is the role of seedling recruitment (as opposed to interactions between adults) in determining community composition and structure? There is, they acknowledge, a major practical obstacle to answering this question; in many long-lived or clonal perennials (and even in annuals that colonize episodic disturbances), seedling recruitment may be rare. Genetic evidence suggests it may, in fact, be more common than we think, but nevertheless it remains difficult to observe and therefore to study. Eriksson and Ehrlén are concerned mainly with herbs, but in a chapter on seedling communities, Keeley and van Mantgem ask essentially the same question for woody plants, with similarly inconclusive results.

Most chapters review published data, but Kollmann presents some new analyses, in an attempt to discover whether we can recognize seedling functional types. It turns out that we can't, not yet anyway.

It's easy enough to decide when the seedling stage begins, but as most of the authors in this book remind us, it can be hard to define when it ends. Moles and Leishman point out another problem for the prospective seedling biologist: other traits (seed mass, for example) have such a powerful influence on seedling size, dispersal syndrome, seedling reserves and seed persistence in the soil that ‘seedling ecology’ is left with rather little room to vary independently. Moles and Leishman tackle head-on probably the single most important question about seedlings: what role do they play in shaping other parts of a plant's life-history strategy? Trying to answer this question provides the most interesting (and controversial) chapter in the book. In a nice foreword, Peter Grubb says he ‘cannot accept all of the assertions in this book’, and neither can I. Moles and Leishman argue persuasively that failure of enough juveniles to survive to maturity prevents plants with long juvenile periods (essentially large trees) from producing very small seeds, but readers should be warned that dissenting opinions exist (Rees and Venable, Reference Rees and Venable2007). In any case, I'm not sure we are asking the right question; very large plants do not produce very small seeds ( < 0.01 mg), but plants with such tiny seeds tend to be parasites, or carnivorous or mycoheterotrophs (at least as juveniles). Maybe a more interesting question is why there are no very large plants with these modes of nutrition?

In a curious section, Moles and Leishman observe (correctly) that there is no close relationship between seed dormancy and either seed mass or persistence in the soil. Unfortunately they then go on to report (without comment) the conclusions of Kiviniemi (Reference Kiviniemi2001) and Venable and Brown (Reference Venable and Brown1988), authors who both hopelessly confuse seed dormancy with persistence (and indeed seem to assume that they are the same thing). Other things are easier to agree with; Moles and Leishman are sceptical (rightly) about the ability of a supposed competition/colonization trade-off to account for seed-size variation within plant communities (I would argue that one could be equally sceptical about the existence of such a trade-off). I'm also inclined to agree that there are fundamental morphological and physiological differences between slow-growing seedlings from large seeds and fast-growing seedlings from small ones, and it's a pity that the recent paper by Turnbull et al. (Reference Turnbull, Paul-Victor, Schmid and Purves2008) came too late to be included here.

A couple of things struck me as odd about the book as a whole. One is that a certain unevenness of approach is always to be expected in such multi-author volumes, but there are some particularly good examples here. It looks like the authors were encouraged (or at least allowed) to place chunks of text in boxes, but only very few have done so. The attitude to figures and tables also varies more than it should do: Hyatt's chapter, for example, consists of 12 pages of uninterrupted text, which doesn't look very inviting. A second odd feature is that there's a lot in this book, but it's still bigger and heavier than it needs to be – for no obvious reason, one-third of almost every page is empty space.

Nevertheless, there's a lot to like about this book, and it could be read with profit by almost anyone with an interest in any branch of plant biology. You will discover not only how much we know about seedlings, but more importantly how much we don't know.