There are two kinds of people who are interested in magic. The first just wants to lean back and enjoy the show. The second wants to know how everything works - and magicians normally won't tell you. In Hiding the Elephant, Jim Steinmeyer, who has designed illusions for David Copperfield, Doug Henning, and Orson Welles, as well as Broadway shows, tells the secrets. Not all the secrets, of course: the book is a history of the use of mirrors and optics in magic. If you are the second type of person, you will love this book. You may, however, never again be able to suspend your disbelief long enough to enjoy a magic show. Steinmeyer could hardly have better credentials to write a book that combines the history of magic with the inner workings of famous illusions. According to fellow magicians, many of the designs on stages today originated with him; he was the one who made the Statue of Liberty vanish for David Copperfield, and he has worked for just about everyone in the business, including Disney.

What is astonishing to the layman is the amount of ingenuity magicians are willing to put into fooling people. Consider, for example, the career of brother–and–sister team Charles and Lilian Morritt, who dazzled 19th century audiences with their mind–reading act. Charles Morritt would walk the theatre and hold items loaned him by the audience in his hands, while his sister, blindfolded on stage, identified each one in turn. The secret was timing: Charles Morritt said very little as he handled the objects, but he and his sister had learned to count rapidly and precisely in synch; the length of the pauses between words conveyed numerical codes that enabled her to identify the items.

But the Morritt's bigger illusions, like those of other magicians profiled in this book, involved optics. Take one of those big, apparently empty boxes that magicians love to make women or elephants disappear in. The key is mirrors that reflect the back of the box and make it look empty. Using a correctly angled pair of mirrors, you can create a safe zone within the box. As long as the woman — or elephant — is standing in that safe zone, she can't be seen by the audience. This sort of principle has been used repeatedly to create crowd–pleasing illusions throughout magical history.

Among the magicians Steinmeyer profiles, besides the Morritts, are the Maskelyne family, the Davenport brothers, Robert Houdin, Harry Houdini, and John Henry Pepper, whose Ghost illusion drew crowds to the Royal Polytechnic in the 1860s. They are, as you'd expect, an eccentric and entertaining bunch. Some are also famous in sceptical circles: the Davenports for claiming to be spirit mediums, and Houdini for busting frauds.

Steinmeyer also reminds us of a principle often repeated by the magicians in the sceptical movement, that children are often the worst audience for magic because they do not yet have enough experience to have developed the assumptions magicians play on. By contrast, Steinmeyer writes, "Anyone with a firm set of beliefs, anyone who has been forced to categorise or analyse information, is ripe for a skillful deception. This is why there are famous and embarrassing examples of learned men of science being badly fooled by the simple tricks of fake psychics."

Magicians work, as Steinmeyer tells us, with a relatively small collection of possibilities, just as people estimate that there are only a handful of basic plots in fiction and there are only eight or so notes in a musical scale (depending on the scale). Objects appear and disappear; they float; they penetrate one another; they can be cut and restored or joined and divided. Magicians can demonstrate what appear to be paranormal phenomena, such as mind–reading, ghosts, or living heads. Depending how you count and define illusions, you're talking about a palette of seven to 19. Yet magicians have used that limited menu to fool everyone in far grander ways than self–proclaimed psychics often do. After all, which is more impressive: hiding an elephant on a fully lit, empty stage in plain sight of 5,200 people, as Houdini did, or moving a glass vial three inches in a scientist's laboratory?

Which is Steinmeyer's even more important point. It's not the tricks, the quality of the machinery, or the size of the illusion that makes a magic show. It's the skill of the magician in creating a story the audience can care about. Houdini, as Steinmeyer says early on, was a great escape artist, but a terrible magician. When he made an elephant disappear at the Hippodrome, says Steinmeyer, the audience barely reacted.

Hiding the Elephant is available from Amazon (UK)