The Plague by Albert Camus.
I just finished reading
The Fall by Camus last night and started this one immediately after. I'm hoping to have it finished by Wednesday so I can re-read
The Stranger for the umpteenth time. I'm having an experiment, how depressed can you get if you read nothing but Camus for an entire week. If I mysteriously stop posting by the 29th I guess we'll have our answer