It's amazing and brave and epic to watch a playwright marshalling some 70 characters, dozens of different locations and shifting time frames, public and private themes and fierce intellectual debate. The playwright in question being Tom Stoppard, all of this emerges in a veritable torrent of words, thoughts and ideas. And the plays in question being The Coast of Utopia - the umbrella title for three separate, sequential but self-contained new works by him receiving their simultaneous world premieres at the National Theatre - there's no stopping the phenomenal verbal fireworks for over nine hours.

On trilogy days - which could be re-titled 'Saturday at the National with Tom' - you can see all three plays in one go, kicking off at 11am and continuing until almost 11pm, including a couple of 75 minute meal breaks (you can also see the plays separately on week nights).

This isn't, of course, the first time the National have invited us to do this - the David Hare trilogy and Tony Kushner's two-part Angels in America also held you in their thrall for the entire day. But both of those events were built separately over time; this is the first occasion that a trilogy, each component individually big, has been premiered at once and in such a massive way, with the same actors appearing in all three plays.

The result is by turns dense and daunting, exhilarating and infuriating. The plays, covering a 33-year time span from 1833 to 1866, embrace a rich canvas of real-life Russian characters as they seek change, both in public politics and in their personal pursuits of love and happiness. The first play, Voyage, introduces us to the ardent future anarchist Michael Bakunin (Douglas Henshall), his family and idealistic friends. These include a would-be writer, Ivan Turgenev (Guy Henry), a literary critic Vissarion Belinsky (Will Keen) and a would-be revolutionary, Alexander Herzen (Stephen Dillane). Stoppard also draws a wonderful, almost Chekhovian portrait of Bakunin's affluent family and life on their country estate, which he leaves behind as he sets forth on a voyage to Germany and the desire to translate thought into action.

In the second play, Shipwreck, the focus shifts to Herzen and the action from Russia to Paris, where - against the backdrop of the 1848 revolution there - the personal becomes political. (It also allows director Trevor Nunn a reprise of his Les Miserables barricade scene). Herzen becomes the mouthpiece for the search for utopia, but even as he strives to reach it, his home life and happiness are shipwrecked in an all-too-real way. Finally, in the third play, Salvage - his family and ideals lost - Herzen finds solace in London amongst a community of Russian exiles, including Bakunin and, seen only briefly, Karl Marx.

Stoppard's has always been a dizzying, even dazzling, talent, and though these plays can feel as if they've been written as much in the research library as they were in the creative furnace, there's also something rich and exciting about his desire to convey so much knowledge and learning. Sometimes reading a book review is a shorthand way of getting a book read for us, so we don't have to - Stoppard has done the same thing for Russian revolutionary thought, distilling the results into a work of art in itself. On the other hand, the whole is greater than the sum of these plays' parts. Because Stoppard has the time, he takes the time, and the resulting drama might have been sharper if it were condensed into only one play.

But there's no doubting that the fluidity of Stoppard's ideas are more than matched by the fluidity of Nunn's stunning production, which unfolds against a cinematic cyclorama screen onto which are projected video images, designed by William Dudley, to perfectly set the unfolding scenes. The huge ensemble cast also contains several fine players, among whom Dillane, Henry, Keen and Eve Best (first as one of Bakunin's sisters, then as Herzen's wife, and finally as a German exile in London) stand out.

- Mark Shenton