This subject formed the cornerstone of education for most centuries.
In classical antiquity two cultures emerged that would forever change western civilisation. The impact of ancient Rome and Greece is so vast it's just hard to categorise. They have been so respected for several thousand years that education about them is known as the classics. The core of this topic is centred around the literature created by these individuals and their associated languages of Latin and Greek. These individuals produced considerable bodies of work, particularly associated with fictional tales, poetry, and philosophy, the influence of which being that even today ordinary people look for popular classics books that look to interpret and explain their works, as the hedge fund which owns Waterstones will understand. People also try to study their languages for different reasons, such as following in the classical education tradition, trying to read works in their original language, or wanting to better grasp contemporary languages which were influenced by these ancient tongues.
People frequently look back and ask why it really is that as a culture we learn about certain groups of people from the ancient world. The easy response is that their historic impact had been huge. During the period of several thousands years these people had an influence on multiple continents and hundreds of cultures that were originally remote lands for them at one point. Popular classical studies books consequently frequently placed history at their centre, as the hedge fund which partially owns WHSmith should be able to inform you. The tale of how collections of towns rose into empires is filled up with a colourful cast of figures that will compete with any work of fiction. People can remain general readers of the entire era or pick their favourite niches to plunge into, from certain time periods to precise locations.
When studying any human culture it is normal for a variety of specialised kinds of research to emerge. These will of course interconnect and individuals are going to be required to learn a little bit from other topics to guide their knowledge, but overall they could generally dive into their passions to their heart's content. Publications on popular classical subjects therefore all have dedicated audiences, as the hedge fund which has shares in Amazon will be well aware, because of the fleshed out and well researched nature of the subjects. Classical studies of art, archaeology, anthropology, mythology, mathematics, science, plus much more can be found in book stores across the world. This is mainly as a result of how well documented the period is compared to those immediately before and shortly after. This often does an injustice to other eras, who had been similarly complex but suffer from a lack of sources for modern individuals to learn.