For most people a 25th anniversary is cause for celebration – a party, a dinner, maybe a few speeches. If you are musical theatre phenomenon Les Misérables however, festivities operate on an entirely different scale. London struggles to support two opera houses, yet this anniversary year will be playing host to three separate (and briefly simultaneous) productions of Boublil and Schönberg’s classic show, including an all-star, cast-of-thousands spectacular at the O2.

A good ghost story never ends. Its twirling impetus sets a narrative top in motion that continues to spin indefinitely in the mind, propelled by the force of a listener’s imagination. As good ghost stories go, The Woman in Black is among the most insidious, having reduced audiences of metropolitan adults to whimpering, night-light clutching infants since 1987.

What sound does a screaming foetus make? It’s not the kind of question that most theatre plays provoke you to ask, but Mike Bartlett’s new piece about climate change is not a normal play. At the end of the first half of this rollercoasting epic, dazzlingly directed by Enron maestro Rupert Goold and which opened last night, the image of a foetus crying out in the womb seems perfectly reasonable. It’s that kind of show; fuelled by a wildly imaginative vision, when it ignites it burns like phosphorous. And, believe me, that changes your perceptions.

Everybody in the business says don’t think Sondheim is easy. I’ve seen galas where big names stumbled in under-rehearsed numbers, and last night Bryn Terfel and Maria Friedman slipped and almost fell on the same banana skins that had done for them in a hastily semi-staged Sweeney Todd. Not enough to matter, though, and they rightly brought the house down. And the show as a whole?

It's very hard to ever know what to expect from Alan Moore, the Mage of Northampton. The author of era-defining comics like Watchmen, V For Vendetta and From Hell has long maintained that art and magic are one and the same, and since the mid-1990s his works have often tended to be long and complex explications of various occult principles, which while eye-opening can often lose readers in all their baroque unfoldings.

With summer now fully upon us, and tourists flocking to the West End, it seems a good time to lift the bonnet on the tireless engine of London’s long-running hit shows. Over the next six weeks theartsdesk will be giving six of London’s hardest-working and longest-running classics – Les Miserables, The Lion King, Chicago, Billy Elliot, The Woman in Black, and of course The Phantom of the Opera – the once-over, checking to see whether all really is still running as smoothly and efficiently as it once was.

Never have the Tudors seemed so real. After decades of TV and film characters keeping us at a teasing, ermined distance, Hilary Mantel's dazzling novel Wolf Hall brings it all to life as never before, and the Globe's still-running Henry VIII has vigorously built on that. But the Stuarts?

This, Heinrich von Kleist’s last play, was completed not long before he committed suicide, aged 34, in 1811, when the map of Europe - and indeed that of his native Prussia - was changing with indecent frequency. It is loosely (very loosely) based on the real Prince of Homburg and events at the Battle of Fehrbellin in 1675, and with its leitmotif of honour, duty and loyalty to the Fatherland, it is no wonder that the play was appropriated (with suitable adjustments) by the National Socialists in the 1930s (it was a favourite of Hitler's apparently) and then fell out of favour in German theatre in the postwar period.

What makes a good piece of theatre? Is it the atmosphere generated? Is it the acting? Or is it the ability to communicate ideas clearly? I don’t mind if sometimes I can’t hear or understand words. In the past, I have been overwhelmed by Polish versions of Dostoyevsky’s The Idiot. I have watched open-mouthed at Kabuki without surtitles and when Federico Garcia Lorca’s Yerma was first seen in this country, in Peter Daubeny’s World Theatre seasons, back in the Sixties, you hardly needed to understand Spanish to be so desperately moved by the sense of yearning emanating from a production played out on a giant trampoline that looked like an enormous cat’s cradle. Lorca, it turns out, is the chosen author for a new production that has its own issues.