Cassell's Dictionary of Classical Mythology
Jenny March
(Cassell, £9.99)

And why should you have a dictionary of classical mythology on your shelves? I ask rhetorically, having just, for private reasons, sacrificed a donkey to Priapus in the back garden. One sacrifices donkeys to Priapus either because (a) he lost to a donkey in a knob-measuring competition, or (b) a timely asinine bray woke up Lotis (or Vesta) just as he was about to ravish her while she slept. Either way, the more dead donkeys the better, as far as Priapus is concerned. As you see, the corpus of classical religion offers so much more entertainment, and so much less hypocrisy, than its tiresome monotheistic replacements.

This is a pretty comprehensive A-Z: over 1,000 entries over 831 pages, all with references to sources. You will still need a copy of Lemprière's Classical Dictionary (atrociously out of print, and not to be confused with Lawrence Norfolk's entertaining novel, Lemprière's Dictionary). You will also want Robert Graves's Greek Myths, because his interpretations of the myths' meanings are mind-expanding, and, rewardingly, just the wrong side of plausible. March also recommends Timothy Gantz's Early Greek Myth, which is good enough for me.

I thought it was all up for the classics 10 years ago when Chambers Biographical Dictionary halved the space it gave to Lemprière and his amazing feat of scholarship in order to make room for Jack Lemmon. A fine actor, but still. Anyway, it's great to see a publisher like Cassell putting something like this out. Dr March can give herself a pat on the back, too: this is a prodigious, authoritative gazetteer, each entry both typographically and stylistically readable, and if you know more than is contained in these pages then you have no need of it. In other words: you have need of this, and a tenner is a very reasonable price to ask.

Let's now moan a bit. There's a five-page list of Greek and Latin authors at the back that could have been usefully extended for little effort. For example, to say that Lucian was a "Greek prose writer and philosopher, born c. AD 125-120, died after AD 180" - and nothing else - is not only insufficient but inaccurate. Never mind whether he was born in Greece or not (he wasn't), or a philosopher (hardly, unless you stretch a point), but would it have hurt so much to have inserted the word "comic" or "satirical" in there? He was one of the funniest writers who ever lived, for Zeus's sake.

What else? You have to squint hard at the map to find out where Boetia is, rather than find it in the index of place names. There's no mention of Comus, the god of revelry, or of the Lycus who was, says Lemprière, "a king of Libya, who sacrificed whatever strangers came upon his coast", and who nearly gave Diomedes the chop when he was shipwrecked there after the Trojan War. March says Diomedes "journeyed safely home to Argos". So poor Callirhoe, who rescued him from her dad and then hanged herself when left behind, died in vain.

These, however, are pettifogging complaints aired only to make me look learned. Anyone who did not know that the warlike Abantes had "mullet" hairstyles is not learned. Have this as your bedside reading and you won't sleep for hours. Neither will I, after that donkey business. Blimey, it really works.