Simon de Pury, 65, is a Swiss baron, art auctioneer and collector who has been dubbed “the Mick Jagger of art auctions” because of his dynamic selling style (he is a DJ too). His new memoir, The Auctioneer: A Memoir of Great Art, Legendary Collectors and Record-Breaking Auctions, ghost-written by William Stadiem, gives us the view from the podium.

To what extent is being an auctioneer like being an actor?
I compare it to being a DJ – you cannot prepare, there’s improvisation, you have to be in tune with your audience. If you conduct a jewellery auction, it is unlike a contemporary art or books auction. I’ve seen auctioneers getting rough with audiences. That’s a no-no. You need to be very polite.

You say “clothes make the auctioneer” – almost as if it people were bidding for you?
I try to be impeccably dressed. And even though today the dress code matters less, I don’t feel at ease without my double-breasted Caraceni suit.

Former Sotheby’s chairman Peter Wilson said: “You have to covet art to appreciate it.” Is that true?
As a young man, I lived in a flat in London without any pictures. In my early 30s, I bought a work by Russian artist Erik Bulatov. Once you have taken that first step and spent money on art, you get hooked. It is no longer enough to look and appreciate, you feel you must own.

What did your hero, the French auctioneer Maurice Rheims, mean when he said, “Distrust objects”?
When you look at an object, it might seem seductive. But condition is important. Examine that old master under a blue light…

You always eat an apple before a sale – how did that superstition start?
I get incredibly nervous before each auction. The apple thing began in 1993. Sotheby’s was selling some of the contents of the Thurn und Taxis family’s castle in Regensburg, Germany – a six-day sale, the auction room was in their riding hall. All over the castle, they had big bowls of apples and each time I’d go towards the podium, I’d eat one. Six days of incredible success – the auction a triumph, I was convinced the apples did it.

Why do you say that when Elizabeth Taylor bid for a brooch of Prince of Wales feathers set in diamonds it would have taken nerve?
It was the first time she’d bought a piece of jewellery for herself instead of being given pieces by her male admirers. Bidding takes nerve. I sometimes bid for clients and try to look cool but inside your heart is beating strongly.

What is the most important thing when wooing a client?
The key is to gain trust. Most collectors have a deep, personal involvement with their artworks – as if they were entrusting you with their children.

Or selling their children…
Definitely not. Three Ds in the art market explain the usual reasons for selling: debt, divorce and death.

You write about Russian oligarchs and the “wild east”. Where are the people with most money now?
The art market has become truly global. Postwar contemporary art markets were dominated by west European and North American collectors. Now you have the former Soviet republics and eastern bloc countries, the Middle East, some African collectors of importance, Latin America and Asia…

Has the internet transformed the life of an auctioneer in a positive way?
Information once only accessible to insiders is now accessible to everybody. It has helped the market become easier to navigate. Art sold online will increase a lot over the next few years, especially if you are selling art between $10,000 and $2m – that segment of the market can be sold more effectively through the internet. At the top end, auctioning will continue in the bricks and mortar way.

You describe eBay as the greatest flea market in the world. Should auction houses keep an eye on eBay for hidden masterpieces?
They should – like browsing in junkshops.

To what extent do you see yourself as a tastemaker?
My years at Phillips de Pury were key. We focused on cutting-edge contemporary art. I’d discuss with my colleagues which artists we believed in. Each season we would sell new artists at auction and the gratifying thing was to see them go on to great careers – we were curating the contents of these auctions. We turned down 80% of what people offered us.

You have become Leonardo DiCaprio’s auctioneer of choice for his charity sales – what is he like?
At big visibility events, it is fascinating to see the difference between people on stage and off. Leonardo DiCaprio is as charming with electricians and sound engineers as with clients and I greatly respect him for that.

Your book is not short of names and each person is described as if they were being valued. An occupational hazard?
My ghost writer is based in LA and when I was Skyping him from London, I’d tell him anecdotes and he would say: “I want names.”

Is it possible to have so much money that it stultifies acquisitiveness?
Funnily enough, that never happens. When you are a collector, it is an addiction – it does not let you go. I’ve seen collectors who were terminally ill make major acquisitions. It is a way of showing yourself to be fully in your life.

You say that for the super-wealthy, such as Baron Hans Heinrich von Thyssen-Bornemisza, for whom you worked, art is the “great validator”, engendering more respect than money or property?
There are as many different motivations as collectors. A cultural legacy is the longest lasting.

Art rises above money?
It puts you on a different level. Baron Heini was received by heads of state everywhere – nothing to do with his business success.

You have consulted clairvoyants in your life. Without their assistance, how do you see your future?
As long as I have health, I hope to do things with the necessary enthusiasm. I did a charity auction with Yehudi Menuhin a few weeks before he passed away. He was conducting a choir of little children as if it were the most important concert of his life. It was so inspiring. I hope whatever I do I can do with that fire in the belly.

The Auctioneer is published by Allen & Unwin (£16.99). Click here to order a copy for £13.93