As an American who has spent a bit of time in London and other parts of the UK, I appreciated this sweeping history of the city. Ackroyd employs an interesting style, choosing to discuss various themes rather than presenting everything in chronological order. As such, it's more a collection of anecdotes and reflections than a conventional history.
The book covers events from pre-history to contemporary times and a little of everything in between. There are anecdotes about the druids, the plague, churches, railroads and the Underground, sewers, class conflict, food & drink, kings & queens, and lots more.
I listened to the audiobook version, narrated very ably by Nigel Patterson. A vast book like this is enjoyable to listen to but the print edition -over 800 pages and illustrated- might be better if you want to retain the information and refer to it later.
I definitely recommend this "biography" of London to anyone interested in the city or traveling there.