Ballet galas are a curious institution. They mimic the form of “Greatest Hits” recordings, but what you get are rarely greatest hits, because they can’t be. Dance develops in its own time, its unfolding being an essential part of the magic. Rip a pas de deux (and galas circle around pas de deux like vultures in the Gobi desert) from its context, and you get pure dance, certainly; flashy dance, more than likely; lots of pyrotechnics, almost inevitably. But you don’t get the core, the magic, the reason people return over and over and over.

Les Grands Ballets Classiques de Stoke Poges are a company waiting to happen for most of us, but for Les Ballets Trockadero de Monte Carlo a bitter rivalry must be endured - one of their ballerinas didn’t show up last night in High Wycombe, due to winging on a last-minute errand of mercy to the Stoke Poges mob. Fortunately Ida Nevaseyneva was available to totter in with her eternally moulting Dying Swan - and all suddenly became right with the world. The Trocks are an errand of mercy, to anyone who loves old ballet, anyone who loves smart comedy.

The specialist book supplier Dance Books is finally closing up, due to the ill health of its longtime proprietor. David Leonard’s little shop long embellished Cecil Court, one of the alleys of literature off Charing Cross Road, London, until 10 years ago he moved out to a former bakery in Hampshire focusing on publishing Dance Now, the last serious dance magazine of ideas, and mail order books retail.

Tonight the company dedicated to the greatest radical of modern dance, Merce Cunningham, opens its farewell tour to London, a valedictory odyssey that will end next year. Last year Cunningham died, aged 90. He had just premiered a work called Nearly Ninety, and this is fittingly the last thing we will see of his company as it blazes one final circuit before closing down in December 2011.

Those teenage lovers Romeo and Juliet will be dying nightly on a stage near you in various guises for much of the autumn - not as Shakespeare’s play, but as ballets and operas based on it. Next week both Birmingham Royal Ballet and English National Ballet field two of the more famous versions on their autumn tours, while at the end of the month the Royal Opera stages a rare revival of Gounod’s opera.

Sergei Diaghilev was not short of self-belief. He appointed himself the man to introduce European modern art to Russia and then Russian modern art to Europe as the 20th century began, and in doing so he defined himself as the ultimate artistic director, as the remarkable, tentacular exhibition at the V&A Museum that opened yesterday shows. Reviewed elsewhere on theartsdesk, the exhibition's mounting has thrown up extraordinary inside dramas - the telltale paper found in the boning of a 1916 tutu, the unlikely discovery of a stellar bust in a junk shop, and the legendary artists' sweat that no cleaning can obliterate.

Sergei Diaghilev was not short of self-belief. He appointed himself the man to introduce European modern art to Russia and then Russian modern art to Europe as the 20th century began, and in doing so he defined himself as the ultimate artistic director, as the remarkable, tentacular exhibition at the V&A Museum that opened yesterday shows. Reviewed elsewhere on theartsdesk, the exhibition's mounting has thrown up extraordinary inside dramas - the telltale paper found in the boning of a 1916 tutu, the unlikely discovery of a stellar bust in a junk shop, and the legendary artists' sweat that no cleaning can obliterate.

This week Scottish Ballet opens its new season with a ballet of genius that began life in the bath. The bath is a great place for inspiration. The Greek mathematician Archimedes discovered the law of hydrostatics in it. The choreographer Frederick Ashton also had one of his major lightbulb moments while having a soak, idly listening to the radio in 1947 when a new piece of music came on.

In the second part of this historic career overview interview with the unique British impresarios, Victor and Lilian Hochhauser talk about their razor-edged relations with Soviet apparatchiks and the pressures they came under to prevent artist defections. Victor (who is a very engaging raconteur) reveals the lengths the Russians tried to go to stop Pierre Boulez conducting Berg in the USSR - liver-busting ceremonial vodka sessions, and a solution of Lewis Carrollian ludicrousness. "I hated them," he says, "but we needed each other."

When the words "commercial" and "art" come together - as they do with the Bolshoi season currently at the Royal Opera House - odds are the glue between them is a three-word phrase "Victor Hochhauser presents". Victor and Lilian Hochhauser are the impresarios behind most Russian ballet seasons UK-wide, and they have a reputation for solid box-office commercial taste, which is easily dismissed as the safe option. But they are in their eighties now, and conservatism is forgivable.

When Russia was plunged into Revolution in 1917, a chief balletmaster inside the Imperial Ballet in St Petersburg feared the worst. It was not simply the death of Tsars he feared, but the death of all culture associated with them, including the classical ballet that had grown to become an opulent wonder of the world. For 25 years all the ballets in the repertoire had been notated, their choreography, how the steps fitted the music, what costumes and sets should be. The notes were filed in several large volumes.