In the cultural world, as everywhere, the pandemic created glacier-sized logjams that began to break, unevenly and sporadically, over the last six months. One of these breaks, a sudden flood of pent-up books, made 2021 a banner year for readers and book collectors. Choosing annual favorites is always agonizing. This December was especially, cruelly so. Here are my top five, in no particular order, with an honorable mention because I just had to.