As the title suggests, this is a work inspired by struggle and challenge, despair at the state of the world and belief in humankind’s capacity for redemption. As they have shown when both leading their own groups and working together, Wadada Leo Smith and Vijay Iyer are able to lend to such themes the necessary emotional depth as well as musical invention.

The soundscape fashioned on ‘Sumud’ makes the point in no uncertain terms. Trailing electronic hiss, like the flicker of a faulty generator, unsettles yet somehow soothes while Smith’s muted trumpet creates vaporous phrases, some long held, some spiraled downwards with mild force supported by Iyer’s acoustic and electric tremolos, which slowly and purposefully build to a measured yet powerful conclusion.

If the net result is a deeply affecting lament, then ‘Floating River Requiem (For Patrice Lumumba)’ is heart stopping for the understated gospel implications of Iyer’s chords and the wry blues of Smith’s melodies, tracing a line from Armstrong to Eldridge to Cherry.

Nothing could be more appropriate for the subject of the Congolese leader eliminated by western forces at a time when neo-imperialism in league with corporate greed rears its ugly head again. Elsewhere digital effects are almost like a distant purr of cellos, and when the brass phrases fragment against the faintest of loops or the gentle hammering of a single icy high note on the keyboard the result is intense. Disciplined, solemn music by two masters of communication that provides a serious response to serious issues.