No, I wouldn't say it's a "must have". Of great interest, of course, to someone who has listened to jazz in Manchester over the years, was at the gigs and knew the local musicians - for someone like that it's something of a personal diary. But the book's style is basically a list of names and dates: " On 18th March X was back again at the Free Trade Hall, this time with a quintet", etc. I don't recall any insights, conclusions or revelations from behind the scenes.
(Sorry about the put down, Big Beat Steve, as I know you're rather keen on this one. )