“Birds travel in flocks, fish in schools. Sometimes books arrive in cohorts, too, testing the attention spans of booksellers, reviewers and, most of all, readers… For publishers and authors, these pileups can lead to a scramble to distinguish their books from the pack, with moved release dates and changed marketing plans. Authors battle to snag talk-show spots. Book reviews often pair books, and booksellers clump them onto a themed table. For readers, this can create confusion, or worse, fatigue.”