Recommended by the good folks at Olman's Fifty and the Mt. Benson Report.
Beginning just days before a nuclear exchange that wipes out most of North America, Europe and the Soviet Union, Pat Frank's Alas, Babylon tracks Randy Bragg as he sets up for, and deals with the aftermath of the attack. Bragg is a man in need of direction and the crisis helps focus him, and, actually, rescues him from destruction from that seductive mistress of alcohol and sheer laziness.
Randy's brother works in Air Force intelligence and realizes that a nuclear war is about to go down between the Russians and the Americans (instigated, of course, by a crisis in the Middle East). So as he heads for SAC in Omaha, he sends his wife and kids to stay with Uncle Randy.
From when they were boys, the two of them have had a code, "Alas, Babylon," which comes from the book of Revelation. Whenever anything bad happened, one brother would say to the other, "Alas, Babylon." When Randy gets a telegram (for readers born after 1985, this is a text message on paper) with the code he springs into action.
His first stop is the grocery store where he buys three carts of groceries, including meat. After the power goes out, the family must eat all of the meat they can in one day and preserve the remainder.
In the midst of his preparation (he hasn't filled prescriptions, gotten candles or other dry goods) the bombs go off. I, too, liked the way this was handled - fishing poles swaying on the rack, a rumble and a shake through the house, and a bright, white light. Just south of Orlando, the town (of Fort Repose) is spared by its distance from cities and military bases.
As soon as the crisis becomes apparent, the town is split into two groups of people: those who can make it (the librarian, the Western Union operator) and those who cannot (the banker and the elderly).
I'll leave the rest of the details to you to discover.
And I could not help but compare this book to George Stewart's Earth Abides. Stewart spends a bit more time on how the environment reacts to the disappearance of so many humans, but maybe Frank does not do so because so much of the earth has become wasteland.
One commonality is the situation that the selfish will impose on the communities of survivors. For Stewart's clan, the threat came in the form of a sexual predator who tried to take/buy/possess one of the community's young women, and who, when warned that this would not be allowed, would not take no for an answer. In Frank's Fort Repose, highwaymen set up shop nearby, robbing people on the road, and then begin raids on outlying farms/houses.
Both situations reinforce that man is his own greatest enemy - both communities were dealing quite well with the lack of social, governmental protection and, for lack of a better word, amenities (like power, water, transportation of goods, etc), but were threatened by the actions of a few individual people. So even after we wipe ourselves out on a large scale, we have to defend against small scale mayhem.
(And I have modified my "shopping" list for when the Troubles come: fish hooks, more band aids, gasoline, and booze (the last two for trade, mostly).)