You name them, he managed them. Wham!, Lisa Stansfield, D:Ream, his third wife Yazz, Scissor Sisters, La Roux, Klaxon, Snow Patrol, Soul II Soul and the rest.
He knew about music. He knew about the business of music.
'If you're a manager and you haven't had a hit, you're a nobody,' he said. 'If you're a manager and your bands are starting to have hits, you're a genius. If you're a manager and you come through a second time with more hits, you're a crook. It's the way it works.'
Jazz Summers knew, and repeated often, that the record industry is about chemistry. He had it with Simon Napier-Bell, his insatiable co-manager of Wham! George Michael and Andrew Ridgeley had it - regardless of the rumours. But, as Jazz was the first to admit, it is also about timing; about knowing when to threaten and cajole or keep silent, when to walk away, when to sign on the line, when to lock people out or to let them in. Above all, he admitted candidly, it was about knowing when and how to tell lies: 'but knowing how to tell them with a point.' At least he was honest about it.
He was fond of saying that the people who run the music business know nothing about music. He wished he'd had a quid for the number of times he was told that 'Careless Whisper' was wrong for radio; that the Verve's 'Bittersweet Symphony' (for which Mick and Keith earned all the money, look it up) didn't have a chorus, so it couldn't be a hit. He got it wrong so many times that people wondered how he had the nerve to keep getting up for more.
'It doesn't matter how many times you go down,' he said, 'it's the getting up that counts. How did I keep going through all the failure? I believed. I believed. These days, when the sorrows get me, I don't drown them in drink the way I once did. I meditate instead. I think about nature. I breathe. I stay in the moment. There are no accidents in life. If George Michael hadn't sacked me, I would never have gone on to do all the things that I have done. Every ending is a beginning. Every mean goodbye a sweet and hopeful hello.'
His favourite book, other than his own autobiography, 'Big Life' (Quartet Books) was Eckhart Tolle's 'The Power of Now'. Its Buddhism-meets-Christianity-via-New-Age-Zen spoke loudly to him. Towards the end of his life - he was seventy-one when he died this weekend - he had mastered the art of letting the past and the future take care of themselves. He warned that none of us has control over our life, and that the more we think we do, the more we don't.
Jazz's big subject was love. It took him four wives to get it right. Dianna was his reward. He lived for his daughters, Katie, Rio and Georgia. He could be so fierce at times, he'd make a grown man cry, but his heart was known to melt at the mention of love. 
'Can you picture a future without them?' he'd say.
'Does every moment of the rest of your life as you imagine it - even though it may never exist - feature that person by your side? Can you imagine growing old without them? Do you value their opinions as much or even more than your own? Do they make you want to be a better person? If not, don't settle. Wait. We all need to be cared for. We all need someone to come home to, someone we can be ourselves with, with whom we can be who we truly are. Most people never find that significant other.They compromise, because time is running out and they think they 'ought' to. If only all these 'most people' knew, that all you have to do is wait.'
Lung cancer took two years to take him. But not really. Every ending being a beginning. Every mean goodbye a sweet and hopeful hello.