Last things first. The final volume of these valuable Channel 4 documentaries is also the least cogent. As Simon Rattle admits, it contains a very personal choice of living composers: what links Birtwistle, Henze and Gubaidulina other than the conductor’s enthusiasm for them? Not a lot. Perhaps the answer lies in accepting that there are no threads: as Rattle put it recently, ‘All music is Balkanised now.’ The excellent ‘book of the series’ (Faber & Faber: 1996) notably departs from its origins at this point for Michael Hall to stir the musical tea-leaves and raise a flag for music that continues to make demands on its listeners and not palliate them.

Volumes 4 and 5 are geographical surveys of sharply different tone. ‘Three Journeys…’ takes us behind the Iron Curtain and suggests that, for Bartók at least, life on the other side was hardly more palatable. Take or leave the uneasy narrative mix of music and politics and focus on the forceful eloquence of Willard White and Anne Sofie von Otter in Duke Bluebeard and Shostakovich’s 14th.

By contrast, no episode wedges more composers or styles into its 50 minutes than ‘The American Way’, and that may be a more telling guide to where the future of serious music lies. Eclecticism bordering on anarchy is meat and drink to Rattle, as is the strong rhythmic impetus that is probably the only quality common to Cage’s First Construction and Weill’s Street Scene.

But it’s Volume 6 that encapsulates the enterprise of ‘Leaving Home’ with most flair. The temporal propinquity of the Four Last Songs (1948) and Gruppen (1959) fuels a discussion of how and why post-war composers wiped the slate clean. It’s certainly hard to view ‘Im Abendrot’ through quite the same rose-tinted glasses after Barrie Gavin’s slant, the long journeys home of wounded and dying soldiers giving new and chilling meaning to Eichendorff’s lines.

Agon gets as much room as any work in the series, its importance as ‘a pocketbook history of music’ explored with tantalising glimpses of what a complete Rattle recording might sound like. At least on this volume the bonus feature comes into its own with a video of the Birmingham leg of Gruppen given as part of the ‘Towards the Millennium’ Festival in 1996. Having registered dismay that ArtHaus did not take the opportunity to upmix the recording to 5.1 sound and come a little closer to Stockhausen’s intentions, I will applaud the daring of Rattle, his teacher (John Carewe) and pupil (Daniel Harding) in taking on this behemoth and the patience and virtuosity of the Birmingham players. The brass trump their forebears on the pioneering composer-supervised recording and, if Abbado’s Berlin Philharmonic (DG, 3/97) dance more nimbly on Stockhausen’s pinheads, they also miss some of the wit behind his crazy time-signatures. The final toot says ‘That’s all, folks,’ like the ‘plop’ at the end of Tippett’s Rose Lake, and Rattle signs off in style.