Interesting. I believe everyone in this thread so far is essentially right, with the possible exception of “reprise”, who would probably admit if pressed that shooting is a bit excessive for any purely linguistic failure. But running down the list:
Montmart - yes, “Now” is awkward in this example, and in many cases like it. You raise a legitimate grump on the usage, which is frequently so clumsy that it disturbs what John Gardner called “the continuous waking dream” of fiction.
barbitua8 - yes, eliminating the adverb “now” would neatly sidestep the objection in Montmart’s proffered example with little or no loss of meaning, as it would equally well in many of the real life cases that drove him to post in the first place.
reprise - your sentiment is clear and understandable.
Jomo Mojo - yes, the authors in such cases are clearly trying to draw the reader into a sense of the moment, while establishing that moment as a particular point in the past. Your example is particularly good, since it is clearly critical in that instance to establish “now” as a point in the fictional chronology, rather than in the reader’s personal timeline.
Snooooopy - yes, and thanks for the great reference! I hadn’t run across the bartleby.com site before, but it’s bookmarked now.
bibliophage - yes, thanks for establishing the venerability of the practice. Clearly it’s not a recent habit of a poorly educated or less demanding age, but a chronic attempt to deal with a common narrative problem.
My own contribution to this discussion is simply to summarize from the above that the practice, call it perhaps the “relative Now”, is just a pedestrian literary device trying to foster a sense of immediacy in the midst of a solidly past-tense narrative. Unfortunately, it is easy to use badly, and in such cases would be better off avoided entirely. But for better or worse, language is still more art than science or math, and this usage is neither legally or morally wrong. All that matters is whether it works, and that will always be a case by case, reader by reader judgement. Although I think developing writers should be warned to consider whether the potential gain is worth the risk.