"It was - let's put this mildly - interesting to listen to this music at Easter. We maybe pay insufficient attention to listening contexts. For all our slightly weird insistence that art, whether of word or sound, is sufficient to itself and needs no external references, when we listen to something can profoundly affect our reception of it.

So, to Easter. There was, inevitably, much said in churches and outside about the natures, acts and reactions of a small group of first century Galileans, gathered round a charismatic healer and prophet whose death seemed to contain a great revelation. Secularists and non-believers will have switched off already and will point out that the recording you are holding is called The Human Factor and not "The Gospel According To . . .", but the parallels with what we are dealing with here are intriguing. Those Galileans are known to us as the Apostles (upper- or lower-case, as you prefer). They were given a message, which they were charged to pass on, and along with it, the authority to invest others with the power to deliver that message, too.

Names in a sense don't matter. Apostleship seems always to involve some kind of suspension of individualism. At which point, you might see where this is going. Modern jazz has often been represented as the art of the individual. The US State Department and CIA rather insisted on this during the Cold War, when jazz (along with abstract expressionisms, jeans and Coke) were offered up as America's response to the hive-minds of fascism and Communism. But jazz began as an ensemble music, as far as we can tell. It may have contained great individualists, but it was about groups and combos and orchestras, not "name" acts.

So, to your probable relief, we turn to a man who has for much of his distinguished career involved himself in performing situations that relegate his name to small print. Heinz Geisser is possibly best known to you as a driving spirit in Collective 4tet (such marvellous albums as Orca, The Ropedancer, Live At Crescent, and Synopsis) and more recently in Ensemble5. (The name might be a puzzle at first, though anyone who remembers other groups who favoured 1 + 1 = 3 titles will understand: the "fifth member" is the guiding spirit of the music itself, not the guest.) But as to the group names that Geisser has favoured, we tend in the Anglo-Saxon West to be a little suspicious of collectivism, or anything that seems to submerge personal identity in any kind of ideology or group-think. But, of course, groupthink in the most positive sense is precisely what improvised music is about and ideology doesn't have to be a doctrinaire rulebook.

A hundred years ago, the missionary Roland Allen wrote a book whose title, Voluntary Clergy, is, quite out of context, my favourite definition of improvising musicians. They are in some sense self-ordained to bring us a message which we then carry forward into our daily lives. It is a message, and you will hear it sounding firmly through the various pieces that make up The Human Factor, that tells us much about how we might live together: sharing, giving way, simple giving, lifting up, helping ... above all, listening.

It has been Ensemble5's practice in recent years to invite a guest to perform at the group's monthly shows. In the spring of 2022, at a moment when the world was still waking up from the dark winter of covid - which also had its unavoidable biblical parallels - Geisser, Fridolin Blumer, Robert Morgenthaler and Reto Staub asked vibist Christopher Dell to join them in performance. So successful was the meeting that recording was convened in the autumn and the music you are hearing ensued.

If titles mean anything, then we might take a highlighter to "Rebirth of the singular" and above all, "The human factor". These extraordinary pieces, which have soundtracked my recent days in so many moods and answering so many needs they have almost acquired personality, are very much about the relationship between individuals and collective identities. It's a subject on which we are deeply conflicted. We admire the individual, even the idiosyncratic, but we also admire ensemble playing (and acting), or the moment when a choir completes the final cadence of a line in perfect synchronisation; it's possible to be moved by such a thing and still appalled by the sight of drilled formation marching.

The first Apostles lived their lives with the heavy tramp of Roman legions on the roads they had built. Jazz emerged and lived through an era of nearly triumphant totalitarianism. Music, and especially jazz, didn't just offer an alternative in the sense of a diametric opposite. Instead, it dramatized the eternal opposition between individuality and collectivism, between "within" and "against" (as Ralph Ellison and James Baldwin both said).

All those years ago, working in China where the Western sense of individualism didn't seem to hold, Roland Allen wrote that "In arriving at a decision in a question of doubt, the apostles" - and we can happily substitute here - "were guided solely by their sense of the spirit behind the action, not by any speculations as to consequences which might ensue". This is the great existential challenge of jazz and improvised music as well. Truth is found in actions whose consequences cannot be predicted. We've somewhat softened this into the advertising slogan "The Sound Of Surprise", but even that bland tag makes an important point. To be a musical apostle, or part of a voluntary clergy, you have to move through hostile or indifferent, or just parched, territory without any plan of action other than the spirit of the moment. No Galilean ever walked the roads alone. It wasn't safe. No true improviser ever works entirely on her or his own account, but always in the presence of a shared spirit. That is what you will hear in these wonderful pieces. The specifically Christian analogy can be gently laid to rest. Its sense of shared endeavour is vital, though."-Brian Morton, from the liner notes