How many books comprise the "Historia Naturalis"?

The "Historia Naturalis," written by Pliny the Elder, is an expansive encyclopedia that covers a wide array of subjects, including astronomy, geography, botany, zoology, and mineralogy. It is renowned for its vast collection of knowledge from various sources, reflecting the author's extensive observations and research about the natural world. The work is composed of 37 books, each dealing with different themes and topics related to nature and the environment.

This number is particularly significant as it embodies the scope of Pliny's ambition to compile all known information and observations of the natural world into a single coherent text. In the context of other options, while 30, 20, and 50 might seem plausible, they do not reflect the accurate count of books in this monumental work. The precise figure of 37 stands as a testament to Pliny’s effort to encapsulate the knowledge of his time into a comprehensive reference, which has held importance in both historical and scientific discourse.