Quite apart from being a concise history of the greatest aphorists of all time from Lao Tsu to Dr Seuss, Mr Geary also gives us a little ready reckoner for our own aphorisms, those expressions that in Mark Twain's definition offer the minimum of sound to the maximum of sense.

1. It must be brief - "When you find yourself in extremis, aphorisms tell you everything you need to know", how about Baltasar Gracians' attempt easy tasks as if they were difficult and difficult tasks as if they were easy?

2. It must be definitive - "Aphorisms assert rather than argue, proclaim rather than persuade, state rather than suggest" like those of Dr Johnson famous for the phrase Patriotism is the last refuge of the scoudrel

3. It must be personal - Aphorisms must bear the hallmark and ideosyncracies of the aphorist otherwise they are simply proverbs - aphorisms that have lost any trace of the mind that originated them.

4. It must have a twist - Ideally they should have a sudden sting in the tail that gives you a jolt, a punch line like that of a joke. Witness Chateaubriand's An orginal writer is not one that imitates no one but one whom no one can imitate.

5. It must be philosophical - "They are like porcupines, bristling with prickly philosophical spines. Rub them the wrong way and you are in for a surprise". Nietzche's good and evil are the prejudices of God is a pretty decent example of that if you ask me. Chamfort's celebrity: the advantage of being known by those who do not know you is pretty good too.

But perhaps the best thing about it is that in one short little book the life and works of some of the greatest thinkers are delivered up in digestable form. No idea about Wittgenstein? Seen all those quotes by Ralph Waldo Emerson on the internet but no clue as to who he was? Want to be able to use Confucius in your next pitch? Then this is the book for you.