Set in a primitive future society and told in the imagined dialect of the time, involving malapropistic phoneticisms and accidental puns (and clearly an inspiration for one story of Mitchell's Cloud Atlas: http://www.goodreads.com/review/show/23327001), so not something you can read quickly - at least, not till you get used to it.
This is the story of a would-be story-teller, trying to make sense of the present in the light of (minimal) understanding of the past, tied in with versions of 20th century life/history (especially the atom bomb) mixed traditional legends such as St Eustace.
Oddly, I found the slang in this (based on mishearings of English) harder than Russian-based slang of Clockwork Orange (http://www.goodreads.com/review/show/335708212), despite the fact I speak English but not Russian. I think that is partly because Burgess is the better, or at least more careful, writer, but also because the whole of this book is written in dialect, whereas in Clockwork Orange, it's conventional English with a generous smattering of slang.
This book, and especially its dialect, were an inspiration to David Mitchell, when writing the central story of Cloud Atlas (https://www.goodreads.com/review/show/23327001), Sloosha's Crossin', as he explains in this article: http://www.theguardian.com/books/2005/feb/05/featuresreviews.guardianreview27
A great book for earnest and intellectual group discussions, but overall, I think it's trying to be cleverer and deeper than it actually is.
Thanks to Jenne, I've discovered this resource: http://www.errorbar.net/rw/. I may have to reread the book!