Throughout history, there's always been a perfectly good reason to start a war. Never more so if it is over a "strategic" piece of old rock in the middle of nowhere. It is, after all, every citizen's right to bear arms to defend what they consider to be their own. Even if it isn't. And in such pressing circumstances, you really shouldn't let small details like the absence of an army get in the way of a righteous fight with all the attendant benefits of out-and-out nationalism.

Fate is a word that springs to the lips when to call something coincidence seems mealy mouthed. Destiny is another such. But the problem with destiny is, of course, that she is not always careful where she points her finger. One minute you might be minding your own business on a normal, if not spectacular, career path; the next you might be in the frame for the big job. Like saving the world.

Sam Vines is a man on the run. Yesterday he was a duke, a chief of police, and the ambassador to the mysterious, fat-rich country of Uberwald. Now he has nothing but his native wit and the gloomy trousers of Uncle Vanya (don't ask). It's snowing. It's freezing. And if he can't make it through the forest to civilization, there's going to be a terrible war. But there are monsters on his trail. They're bright. They're fast. They're werewolves. And they're catching up.

An aura of mean-minded resentfulness is thick in the streets of Ankh-Morpork. Insurrection is in the air. The Haves and Have-Nots are about to fall out all over again. The Have-Nots want some of their own magic. But magic in the hands of amateurs is a dangerous thing. The City Watch is the last line of defence against such unnatural goings-on. But when even the Watch have trouble telling right from wrong, you know that law and order ain't what they used to be. But that's all about to change.

This isn't real life. This isn't even cheese mongering. It's opera - where the music matters, and where an opera house is being terrorised by a man in evening dress with a white mask, lurking in the shadows, occasionally killing people, and, most worryingly, sending little notes, writing maniacal laughter with five exclamation marks. Opera can do that to a man. In such circumstances, life has obviously reached that desperate point where the wrong thing to do has to be the right thing to do.

Mightily Oats has not picked a good time to be priest. He thought he'd come to the mountain kingdom of Lancre for a simple little religious ceremony. Now he's caught up in a war between vampires and witches, and he's not sure there is a right side.

Other children receive xylophones. Susan just had to ask her grandfather to take his vest off. Yes. There's a Death in the family. It's hard to grow up normally when Grandfather rides a white horse and wields a scythe: especially when you have to take over the family business, and everyone mistakes you for the Tooth Fairy. And especially when you have to face the new and addictive music that has entered Discworld. It's lawless. It changes people. It's called Music With Rocks In.

Commander Sam Vimes of the Ankh-Morpork City Watch had it all. But now he's back in his own rough, tough past without even the clothes he was standing up in when the lightning struck. Living in the past is hard. Dying in the past is incredibly easy. But he must survive, because he has a job to do. He must track down a murderer, teach his younger self how to be a good copper, and change the outcome of a bloody rebellion. But there's a problem: if he wins, he's got no wife, no child, no future.

Koom Valley? That was where the trolls ambushed the dwarfs, or the dwarfs ambushed the trolls. It was far away. It was a long time ago. But if he doesn't solve the murder of just one dwarf, Commander Sam Vimes of Ankh-Morpork City Watch is going to see it fought again, right outside his office. With his beloved Watch crumbling around him and war-drums sounding, he must unravel every clue, outwit every assassin, and brave any darkness to find the solution. And darkness is following him.

William de Worde is the accidental editor of the Discworld's first newspaper. Now he must cope with the traditional perils of a journalist's life: people who want him dead, a recovering vampire with a suicidal fascination for flash photography, some more people who want him dead in a different way and, worst of all, the man who keeps begging him to publish pictures of his humorously shaped potatoes. William just wants to get at the truth.

It is a truth universally acknowledged that a policeman taking a holiday would barely have had time to open his suitcase before he finds his first corpse. And Commander Sam Vimes of the Ankh-Morpork City Watch is on holiday in the pleasant and innocent countryside, but not for him a mere body in the wardrobe. There are many, many bodies and an ancient crime more terrible than murder. He is out of his jurisdiction, out of his depth, out of bacon sandwiches, and occasionally snookered and out of his mind, but never out of guile. Where there is a crime there must be a finding, and a chase....

It's the night before Hogswatch. And it's too quiet. It's the night before Hogswatch. There's snow, there are robins, there are trees covered with decorations, but there's a notable lack of the big fat man who delivers the toys. He's gone. Susan the governess has got to find him before morning; otherwise, the sun won't rise. And unfortunately, her only helpers are a raven with an eyeball fixation, the Death of Rats, and an "oh god of hangovers".

Reality is all very well in small doses. It's a perfectly conventional and convenient way of neutralising the imagination. But sometimes when there's more than one reality at play, imagination just won't be neutralised, and the walls between realities come tumbling down. Unfortunately there's usually a damned good reason for there being walls between them in the first place. To keep things out. Things who want to make mischief and play havoc with the natural order.

Religion is a controversial business in the Discworld. Everyone has their own opinion, and indeed their own gods - who come in all shapes and sizes. In such a competitive environment, there is a pressing need to make one's presence felt. And it's certainly not remotely helpful to be reduced to be appearing in the form of a tortoise, a manifestation far below god-like status in anyone's book. In such instances, you need an acolyte, and fast - preferably one who won't ask too many questions.

Never let real life get in the way of a good story, especially when a good story involves three witches, including a fairy godmother, and travelling to a faraway land to make sure that a servant girl doesn't marry a prince. It looks as though a happy ending may be averted before catastrophe strikes. But unfortunately, the forces of good are up against a godmother who has made Destiny an offer it can't refuse.