What an incredible novel/autobiography. The depth of Amis' voice. The stories he tells. The relentless storytelling. This is as good as Money or London Fields. It left me not only with the feeling I'd just read a great novel, but that I better understand the man who Martin Amis is, outside what the tabloids have reported. 
The insights into Bellow, Hitchens, and Larkin add immensely to this. The relationships Amis had with these men, all varied, adds not only to the story but to a better understanding of the depth of Amis' ability to give of himself.
In the end, Amis says this is his final 'long' novel. I suspect this is true. The energy and focus needed to finish a long novel is overwhelming at any age. And the theme here is... death. The end. A movement to the end of time. 
My hope is we get another few short stories. A couple of novellas. Amis' voice has always been unique, but at times it feels essential.

I've noted before that when it comes to memoir, I either want writers to tell me a life story that is so unusual that I learn something new about how others live, or alternately, I want them to use their personal biographies in order to illustrate something universal about all of us; either give me some new knowledge or unveil something relatable. That's it. With Inside Story, Martin Amis doesn't satisfy my (admittedly personal, perhaps unfairly limited) brief regarding memoir, and despite his reminder throughout that this is actually a novel, it reads like a celebrity autobiography; and a frequently dull and self-indulgent one at that. I appreciate the space that Amis devotes to the passing of his closest friends, I like his reflections on the craft of writing, and I suppose it has value for “Martin Amis scholars”, but I cringed every time the narrative returned to Amis' relationships with women (and particularly so with “the alluringly amoral Phoebe Phelps”, as described in the publisher's blurb; what a creepy and exploitative relationship that seemed, and especially as dissected with Amis' pals), and as for the rest (Amis' thoughts on politics and religion and literature), not much is sticking with me a few days after finishing this. I can see how Inside Story might be more engaging for another reader, but it didn't really work for me.