Classic though this is, it was hard to really enjoy A Journal of the Plague Year. It was written before the novel form was really developed (at least in England) so it has very little narrative structure, no real plot, and (worst of all) not a single break in the narrative, making it very hard to put down and pick back up. It was also the first (or near first) piece of historical fiction -- mainly because the dividing line between history and fiction was so much looser. It is probably more palatable to a modern reader if read as a history text -- then the insertion of all the weekly bills is less surprising -- but historians have quibbled with quite a few of the facts Defoe reports.
Still, there were plenty of passages that were absolutely riveting. It is a must-read for anyone interested in the development of the novel form, anyone interested in plagues and epidemics in history, and anyone interested in the history of London -- it simply has to be taken on its own terms.