Rhetorica ad Herennium is a gem of ancient literature. One of the first books to describe the concept of Memory Palace, a mental tool for memory improvement, it was written for public speakers of ancient Rome. While the book's authorship is disputed, it is often attributed to Cicero, one of the greatest orators of ancient Rome, and a prolific author in his day. Aside from providing keen insights into the art of rhetoric, as it was practiced in ancient Rome, this book remains relevant today to anyone who wants to improve his memory.