To some extent, the answer to this question depends on the type of book you've written. For example, books about new beginnings or how to be healthier are often published at the beginning of a new year. For most books, however, January is not a great time to publish. The most popular months to publish a book are late August through early November for the fall market and mid-February through early June for the spring market. Summer months are best for lighter reads or "beach reads," as these are typically slower book-buying months. The best days to publish a book are Tuesday, Wednesday, or Thursday. Of course, all of this is simply guidance. If there's a particular holiday, month, or day that holds special significance and relates to the book, this can be an important factor to weigh.