Taken with a pinch of salt

Why would you have found the Tsar of all the Russias and a myriad candles underneath Cheshire at the end of the 19th century? What can be used to clean both bamboo furniture and, according to Milton, new-born babies? How can you get rid of poison ivy ? What were 3,000 soldiers looking for along the banks of the Loire in 1771?

Yes indeed, salt. White, pink, grey, black, skimmed off the sea in flaky blossoms, deep-mined, iodized or treated with magnesium carbonate for a smoother trickle, amassed into a Catalan mountain, flat out as a dried lake 100 miles long, displayed in several pillars to credulous tourists round the Dead Sea as all that is left of Lot's wife, salt has been the mainstay and the downfall of empires. Venice and Liverpool rose on trade in salt; the Habsburgs dominated salt-starved regions like Hungary because Austria held huge rifts of it in places such as Salzburg ("salt-town"). They were actually drilling for salt when they struck the petroleum in Texas - impenetrable crusts of sodium chloride trap decaying organic matter, so the presence of salt often signals oil or natural gas. Mr Bush may have ungratefully cursed his salted pretzel but he was choking on an element of his own power-base. And where would the Mormons be without it ?

Mark Kurlansky's sparkly book tells you most of these precious facts as well as some things which are not, alas, facts. He's quite right that we owe the words "salary", "salad" and "salami" to the Latin for salt (he could have mentioned "sauce" as well) but neither "sterling" nor "salacious" has anything to do with the white stuff, as he claims. The first illustration in his book is dated 400 years earlier than it should be and he's grotesquely wrong about the Albigensians. These little things matter because they make you wonder whether you can always trust his other pearls of information. I mean, I'd like to believe that caviar was served as a free bar-snack in the pioneer days of the USA (it figures in all too few Westerns) but feel a sneaking need for a grain of salt here as elsewhere while I read.

Anyone worried about his or her skills as a conversationalist at dinnerparties should buy this book at once. You can't go wrong. If your host is a sensible person, there will be salt on the table - food, after all, is merely an excuse for the consumption of salt; if you're in a house that's been terrorised by nutritionists, the exquisite crystals will be notably absent. Either way you have a cue to say, for example, "and to think how the sun began to set over the British Empire on 6 April, 1930 when Gandhi bent down and picked salt from the shore of the Arabian Sea" or "wasn't it Cassiodorus who remarked that though there may be someone who does not seek gold, there never yet lived a man who does not desire salt?" or even "I hear there's a Chinese book from the first century AD which links salt to high blood pressure, funny how long it takes people to listen to advice". You may not be invited back but you will have made a mark of sorts.

Dr Johnson wrote: "How small, of all that human hearts endure, / That part which laws or kings can cause or cure". Lawyers, kings (or prime ministers), and many historians would like to persuade us otherwise: summit conferences, initiatives and "major speeches" are supposed to be what counts. But the actuality of most human lives, now as then, has more to do with cabbages than with kings, with salt than with SALT or similar treaties. This good book reminds us of those small, perdurable realities which the clamour of the state would like us to forget. It remains true, even in our world awash with expertises, that, as Kurlansky writes, "there is still no set explanation for the saltiness of the sea".