Palindrome is a word, phrase, verse, or sentence that reads the same backward or forward. For example: A man, a plan, a canal, Panama!

Some said that palindrome definition means a segment of double-stranded DNA in which the nucleotide sequence of one strand reads in reverse order to that of the complementary strand.

However, the word palindrome is derived from the Greek palíndromos, meaning running back again (palín = AGAIN + drom–, drameîn = RUN). A palindrome is a word or phrase which reads the same in both directions. Some simple examples are:

RACECAR, DEED, LEVEL, PIP, ROTOR, CIVIC, POP, MADAM, EYE, NUN, RADAR, TOOT,

Words like LIVE and STRAW (which read EVIL and WARTS backwards) are not themselves palindromes but the "phrases" LIVE EVIL and STRAW WARTS are. A palindrome is not necessarily a single word.

The longest single English word in common usage which is a palindrome is REDIVIDER, although the contrived chemical term DETARTRATED is two letters longer. In Finnish there is a 25-letter palindromic word: SOLUTOMAATTIMITTAAMOTULOS which means the result from a measurement laboratory for tomatoes, although technically it is a compound of four words. There is also the equally long SAIPPUAKUPPINIPPUKAUPPIAS which means soap cup trader.

When creating reversible sentences, it is usually accepted that punctuation and word spacings are ignored, and so the famous MADAM, I'M ADAM is a valid palindrome.

Palindrome Varieties
There are two other types of palindrome, although neither is particularly common. The first is the word-unit palindrome. As the name suggests, these are palindromes in which the words form the same sentence in either direction, e.g. WOMEN UNDERSTAND MEN; FEW MEN UNDERSTAND WOMEN. Occasionally these are also traditional palindromes, such as in I DID, DID I? but this only happens when each word is itself a traditional palindrome.

The other kind of palindrome is the mirrored palindrome. These are palindromes which are graphically reversible. Not all letters in mirrored palindromes necessarily have symmetry about a vertical axis (A, H, I, M, O, T, U, V, W, X) since some letters are (more or less) mirror images of others (e.g. L and J). Therefore a mirrored palindrome is not necessarily also a traditional palindrome. Punctuation and spaces cannot be ignored when creating mirrored palindromes.

When reversed A TOYOTA becomes ATOYOT A which, strictly speaking, is not the same. WOT TOW, although fairly meaningless, is a valid mirrored palindrome. Of course, with this type of palindrome, it is important whether upper or lower case letters are used: bid is a mirrored palindrome, but BID is not.

This sequence of numbers is called the Fibonacci Numbers or Fibonacci Sequence. The Fibonacci numbers are interesting in that they occur throughout both. Fibonacci Sequence describes the mathematic theory behind the numbers.

The outer ring of ray florets in the daisy family illustrate the Fibonacci sequence extremely well. Daisies with 13, 21, 34, 55 or 89 petals are quite. Can you predict what the next numbers will be in each of these strings of digits?

123454321234543212...
11235813213455...
993751058209749...

The first sequence has a clear rhythm to it. The second is a little more tricky, but look closely and you might notice that it uses the previous numbers in the string to build the next one. This is the Fibonacci sequence, nature's favourite set of numbers and the first code to be cracked in Dan Brown's The Da Vinci Code. The third sequence is much trickier.

At first it looks random but if you come at it armed with the right knowledge you might recognise that it is part of the decimal expansion of pi, starting at the 44th decimal place. Once you know this you have total control over the sequence and can predict every twist as it speeds off to infinity.

There is a tendency within our society to view science with suspicion, whether it is stories of nano-robots infiltrating our body and messing with our DNA, black holes appearing in the Large Hadron Collider in Cern that will swallow up the universe, or genetically modified crops sweeping the world and destroying all in their path. All scientific progress involves steps into the unknown, and that inevitably entails risk. That is why books like this are valuable. Once you know about the science and its implications, you are in a much better position to distinguish sinister developments from mere hype.

So when it comes to Baker's numerati, all of us have a responsibility to understand how much companies and government can or cannot use or abuse the maths. This book won't make you an expert on how the mathematicians do their tricks, but it will make you more aware of the the implications. Read it and you'll have a much better idea of who has got your number.

• Marcus du Sautoy is the new Simonyi Professor for the Public Understanding of Science at the University of Oxford and author of Finding Moonshine (Fourth Estate).

Using Fibonacci sequences in knitting or weaving patterns.

Mathematics is all about spotting patterns, finding the underlying logic in the seemingly random and chaotic world around us; and using this information to predict future behaviour. Traditionally maths has been used to make predictions about inanimate objects, like the orbit of planets or the weather. But as Stephen Baker explains in The Numerati, mathematicians are increasingly turning their attention to human behaviour.

What if those strings of numbers are records of the things you've bought, places you've travelled to, websites you've visited, parties you've voted for? Fibonacci sequences? Find the pattern in the numbers and mathematicians will be able to predict, with surprising accuracy - what your next move will be. The 'numerati' is the name Baker gives to the group of latterday fortune-tellers whose job it is to decode our behaviour. His book explores the lives of such people and attempts to analyze how powerful they have become.