'A Faustian masterpiece'?
Under the Volcano - Malcolm Lowry
This does seem generally to be regarded as a masterpiece, including by Burgess. Recounting the last day in the life of the former British Consul (Geoffrey Firmin) in a fictional Mexican town at the foot of Popocatapetl, it is a quite remarkably intense and stylistic exploration of an alcoholic descent during the celebrations on the 'Day of the Dead'. The Consul's ex–wife and his brother join the party but prove unable to divert Firmin from the inevitable and indeed Yvonne Firmin dies too.
Whilst not the most cheering of reads, this does deserve significant plaudits although I suspect the time of its peak popularity, the 60s, had more to do with some kind of druggy/mescal alignment than anything else.
Anyway, pretty great stuff and certainly one of the most compelling and hellish descriptions of extended drunkenness I have read.