Contemporary jazz is a world full of magpies – artists who flit between genres and build glittering nests of disparate musical influences. Rock up to a so-called jazz night today and the repertoire can come from anywhere, you’re as likely to hear Jimi Hendrix or J. Dilla as Jerome Kern, and pianist Brad Mehldau has played a role in making that happen.

With a moto perpetuo of looping accompanying figures in piano and bass underpinning a memorably angular melody in the sax, the opening track of The Day I Had Everything, ”Squared”, announces both a cliché-free collection and a work of trenchant individuality.

How, exactly, are you supposed to review a Keith Jarrett concert – solo, completely improvised, just one man and his Steinway, audience on all sides, ushers walking up and down the aisles bearing signs forbidding any record of the evening's music?

“I’m sorry I’m late,” said Cassandra Wilson to a half empty Royal Festival Hall, after a sulky rendition of “Don’t Explain”, the opening track from her Billie Holiday tribute album, Coming Forth By Day. It was an hour and fifteen minutes since the singer was due on stage and half an hour since the directors of concert promoter Serious had arrived in her stead – amidst boos and irate whistles – to tell us she was refusing to leave her hotel room.

Don’t blame the players: they did their considerable best. But what could they hope to achieve with a programme in which six of the seven pieces were on a hiding to nowhere, or too short to have much of an impact? A sequence, what's more, in which platform rearrangements took longer than two of the pieces in the first half?

Eloquent, transfixing, profoundly moving. Last night, in the beautiful setting of the Cadogan Hall, the Maria Schneider Orchestra gave one of those landmark performances that people will remember for years to come. We heard seven of the eight tracks from the composer, arranger and bandleader's stunning latest release, The Thompson Fields, which celebrates its composer's love of her childhood home in Windom, southwest Minnesota.

Having released a self-titled debut album last year, soul singer Jarrod Lawson has been on a European touring offensive for much of this one. Very charming it has been, too, landing Lawson Soul Artist of the Year title at the 2015 Jazz FM Awards, and a string of stellar album reviews. Saturday’s London Jazz Festival appearance – there’s a lot of jazz in Lawson’s harmonic keyboard adventures – was the final night of a month-long European tour. On the evidence of the Shepherd’s Bush crowd, he already has loyal fans who know his music, and their number is increasing rapidly.

Featuring the usual, divertingly eclectic mix of singers from the worlds of jazz, pop and soul, last night’s Jazz Voice announced the opening of the 2015 EFG London Jazz Festival with a programme that satisfied both aficionado and newbie alike. Arranged, scored and conducted by the unceasingly inventive Guy Barker, the epoch-spanning celebration of jazz-related anniversaries, birthdays and milestones stretching back from 2015 was hosted by the mellifluously voiced BBC Radio 3 presenter, Sara Mohr Pietsch.

For an art form that has been quite often written off over the last half century, Jazz seems in extraordinarily rude health. Today sees the opening of the biggest ever EFG London Jazz Festival featuring scores of venues and hundreds of groups throughout the capital.

Maria Schneider is one of the luminaries of contemporary jazz.