An almanac or almanack is an annual publication containing a whole year's calendar details, astronomical data, and general information, which varies by publisher, theme, or intent. Its roots are in the ancient ecclesiastical calendar, and predate the use of the printing press.
The first American almanac, Almanack Calculated for New England, was printed in 1639. The Old Farmer's Almanac, first published in 1792, is in the 230th edition in 2022. It has, for over two centuries, helped to predict the weather (with a track record of 80% accuracy!), and share stories on small farmers, tips on animal tracking, and includes some simple recipes and remedies for readers. Published in September of 2021, the 2022 forcast told us to "prepare for a Season of Shivers", which is, by all accounts, 100% accurate.
This cross-section of almanas from our American Almanac Collection in RBSCP shows the wide range of printers, themes, and varients to this annual publication. They are ephemeral because they expire and are replaced with a new version each year, but eternal in the way they share information and provide some insights into the past. An author, writing historical fiction, might be well-advised to consult an almanac for the year that they are writing about!