A Pocket Guide to Shakespeare's Plays by Kenneth McLeish and Stephen Unwin (Faber & Faber, pounds 7.99)
You've got your ticket, booked the baby-sitter and even parked the car. Your next problem will be working out what Shakespeare's saying. While traditionalists may bemoan a culture that relies on pass notes for those who slept through their A-level Bard, today's time-strapped playgoer will appreciate the sneak preview offered by Kenneth McLeish and Stephen Unwin's handy guide to Shakespeare's 38 plays - all in 250 pages. I tested it on the way to the RSC's Cymbeline at the Barbican.

Sure enough, it fits my pocket and each play can be studied in half the time it takes London Transport to get you there. I skip the paragraph on the play's sources, on the basis that all it tells you is that Shakespeare ripped off his plots. Instead, I plunge into the synopsis. Since I had always thought Cymbeline was a woman, McLeish and Unwin soon put me right. Cymbeline was an English king in Roman Britain and the play is a love story about his daughter Imogen, with its share of the usual twists and turns, cross-gender disguises and magic potions. Very promising. Next, I skip the cast-list and move on to the description of the main characters. Although named after the father of Caratacus, Cymbeline turns out to be "a fairytale king", a kind of "holy innocent", while Imogen is one of the "practical but confused" heroines familiar from Twelfth Night and As You Like It.

Great; now I'm ready for the short essay on the play. Cymbeline is "a notoriously difficult play": my heart falls. But, if it lacks "passages of soaring genius", it is "rich in psychological and political detail", offering an "almost mystical vision of peace and unity". After a few thought- provoking paragraphs about the piece's themes, I'm ready for curtain up.

McLeish and Unwin's guide works better for the little-known works than for greater plays. Take Hamlet: except for the insight that it is "one of Shakespeare's most experimental works", this masterpiece is poorly covered. Novices will find it hard to follow the synopsis because the relationship between Claudius and Gertrude is not made clear at the start; experts will sneer at the shortness of the essay.

The main problem with guides is that they are usually too advanced for beginners and too banal for buffs. But as McLeish, who died last November, was a top translator with more than 80 books to his name, and Unwin is the head of the English Touring Theatre, theatre-goers are in safe hands. They will find this guide more useful than most programme notes, while students will find it more provocative than the average crammer. Pedants may scoff, but many solitary theatre-goers will find it a reliable companion: accurate, vivid, a foil for your thoughts - and even a help with the cryptic crossword. If such guides are necessary in today's climate, then, as the Bard said, "There is virtue in necessity."