Who could resist the "Ying Tong Song"

A cry roars forth from a Mercedes. It's Simon Schama. We swing into Fifties mode and Perry Como imp

A week of heavy launching. I always enjoy the autumn publication season, and having a book of one's own amid the cornucopia adds an extra tang. As I've been asked to do Start the Week, I get to see the Velázquez exhibition at the National Gallery while the paintings are still being hung. The saints, the potentates and the princes of the church are magnificent. But it's the domestic scenes, the poetic within the prosaic, which captivate, especially An Old Woman Cooking Eggs and Kitchen Scene with Christ in the House of Martha and Mary. Larry Keith's chapter in the catalogue on Velázquez's technique is fascinating about his recreation of the fish in Kitchen Scene - you can almost smell them.

History's boom

Off to Cheltenham for three very different shows. First, Diane Purkiss, David Horspool and I debate "whither history" to accompany the Times Literary Supplement. The TLS last undertook a grand "whither" in 1966, when the future of narrative history was pronounced bleak. Au contraire, say I. We live and write as much as ever in the shadow of Macaulay and G M Trevelyan. If and when we cease to, the history boom will bust.

The next morning I fly solo on my Fifties book, Having It So Good. The main hall in the Cheltenham Town Hall has been repainted and, more than ever, speaking here is like performing inside a wedding cake. It is 50 years to the day since French emissaries called on Anthony Eden and tempted him into the disastrous collusion with Israel. Plenty of people of "my age" remember that Suez autumn and there's a good deal of experience-swapping at the book signing.

Final performance that afternoon about the writing of obituaries, with Mary Ann Sieghart, Anthony Howard and Roy Hattersley inside the wedding cake. It's attracted a huge crowd. Over tea, before we begin our exhumation, as it were, Mary Ann wonders why. The hall, I explain, will be laced with intelligence people from GCHQ. They can't be identified while they're alive but they look forward to their obits letting others know that they did good things for the Queen. To my faint embarrassment, Mary Ann uses this in her opening!

Magic moments

On the way to Broadcasting House for Start the Week, a cry roars forth from a Mercedes: "Hennessy!" It's Simon Schama, who leaps out and embraces me. We swing into Fifties mode and Perry Como impressions and the vaudeville barely stops until we're in the studio. David Baddiel, standing in for injured Andy Marr, suddenly has a real job on his hands. Charles Saumarez Smith says he loves Simon's Power of Art book but doesn't care for the use of actors in the TV series. Simon is hurt and the atmosphere turns electric. Jenny Uglow and I are on safer ground with Thomas Bewick and Harold Macmillan. Charles and Simon continue their debate once we're finished. I relish Simon's approach. Nobody does pictures-that-biff better.

Another dip into the secret world when Gill Bennett launches her life of Desmond Morton, Churchill's Man of Mystery, at the Cabinet War Rooms. Sir David Omand, the former Cabinet Office co-ordinator of security and intelligence, delivers an elegant speech on the danger of courtiers in Whitehall. He has a particularly good line at the end: "Knowledge is power, and secret knowledge is supercharged power."

Sir Roger Bannister is the star of my own launch in the People's Palace at Queen Mary. His sub-four-minute mile in May 1954 is one of the great moments of the Fifties; the picture of him breasting the tape is on the spine of my book.

Introducing him, his old friend Sir Michael Quinlan brings the house down by saying, "Roger will speak for exactly three minutes 59.4 seconds!" The night's other hits are Edgar Anstey's Holiday, shot in Blackpool in 1957, and the 29 Fifties tracks compiled by my musical adviser, Andy Dalton. Perry Como's "Magic Moments" and the Goons' "Ying Tong Song" - who could resist?

Peter Hennessy is Attlee Professor of Contemporary British History at Queen Mary, University of London. His "Having It So Good: Britain in the Fifties" is published by Allen Lane, the Penguin Press (£30)