Dig deep for the nuggets to spark the gold rush

Who needs it?" Igor Stravinsky's standard question about a new musical work by a composer other than himself seems out of place in the case of a work of art, but it is bang on target when yet another series of textbooks is launched - especially, perhaps, in philosophy, where it is harder to point to the growth of knowledge as a pretext for adding to "the groaning library shelves", as one of the authors under review puts it.

The publisher needs a series like this because he wants a slice of the action: there is more money in textbooks than in monographs. So he must convince enough readers that the books on his list are better than their many rivals. In the blurbs for all five books that inaugurate its Key Concepts in Philosophy series - described as "concise, accessible and engaging" introductions - Continuum tells us, in more identical boilerplate language, boldly infinitive-splitting, that "philosophy undergraduates will find this an invaluable aid to study, one that goes beyond simple definitions and summaries to really open up fascinating and important ideas and debates".

Concise? The longest book is nearly half as long again as the shortest. Accessible and engaging? On the whole not. Most of the books are quite tough going, which is partly the price paid for going "beyond simple definitions and summaries", but also the result of a failure to empathise with the uninformed - the most common, and perhaps the most damaging, shortcoming in a teacher.

An even more serious difficulty bedevils an enterprise of this kind, however well executed. A beginner is usually more easily enthused by a first-order work of original philosophy, judiciously chosen, than by a somewhat detached tour d'horizon , which is rather like a tourist guide to a place one has not visited. "Visit sunny Epistemology! Explore romantic Logic!" The guide will mean so much more if read on site or at home after the trip. When I was a philosophy undergraduate, we were never given textbooks to read, but were thrown straight into classic texts.

Eric Matthews on Mind , for instance, summarises and makes considerable use of Wittgenstein's famous "private language argument" against our intuitive view of what is going on when we talk about our conscious experiences. A closer encounter with Wittgenstein brings this issue to life and equips the reader to resist Matthews's (and Jose Medina's) too ready acceptance of this far from knock-down argument.

Matthews writes well, but some of the books badly need more editing. Dwight Furrow on Ethics has a contorted and often opaque style that does a disservice to his views, which are in any case odd in themselves. "When, through our actions and attention, we succeed in making the good that is available to us persistently visible in our lives, we are justified in asserting our happiness." Hello? There are also too many misprints in his book; an index that cites a passing mention of the film The Silence of the Lambs but has no entry for pluralism (a recurring topic), will not do.

Christopher Norris on Epistemology conveys a sense of excitement that one misses in the other books, but he squanders this advantage by writing obscurely and repetitiously. Repetition is not clarification, and this reader was barely hanging in there much of the time. Given the snowstorm of undefined jargon that Norris subjects us to, it is hard to understand why he thinks his book "accessible... to readers with a genuine but non-specialist interest in the field". At its heart, despite a seductive overture and coda, it is a monograph with no place in a series of introductions (as its 24 pages of notes testify).

Things are no better in Medina's Language , which, after minimal foreplay, plunges us into a dense jungle of pretentious pseudo-technical terminology (much of it of Continental origin) that mostly obscures rather than illuminates its subject. Medina knows a lot, and perhaps understands it, but his account of it is massively frustrating. He keeps shouting at the reader by putting terms in italics , but raising one's voice is not clarification either. He almost never gives the concrete examples that might bring his elusive abstractions down to earth, in particular his accounts of the indeterminacy or relativity of meaning. Indeed, his failure to exemplify is at times breathtaking. This fault is part of the failure, already mentioned, to stand in the novice's shoes.

The best understanding of writing textbooks is shown by the four joint authors of Logic . They meet their readers on the latter's own ground, proceed at a manageable pace (but without becoming boring) and lace their expositions with a disarming sense of humour. Logic is a brain-stretching topic for most of us, once the basics are dealt with, and fierce concentration is needed to follow the more advanced sections of the book; but the authorial foursome keep us on their side by the consideration they display towards us. Admittedly, theirs is a subject particularly suited to textbook treatment, and this may have helped them come out on top.

To read these books one after another is a reminder that a series of this kind needs a firm hand on the collective tiller if it is to sail in convoy convincingly. Not only is the range of lengths and (crucially) levels too great, but the apparatus is too various: three books have notes, two have no bibliography, two use Harvard-style references, only two offer guides to further reading (split by chapter in one case, integrated in the other), and Norris's index is irritatingly confined to proper names. Added to the books' substantive difficulties, this indiscipline seems sloppy rather than flexible.

One palpable hit out of five is better than none. There are occasional flashes in the pan elsewhere, too, but not enough to spark a gold rush. In reply to Stravinsky's question, one has to say that, viewed as a package, this series is unnecessary.

Henry Hardy is a fellow of Wolfson College, Oxford.