No other subject has inspired so much literature than religion, and the genre of religious literature continues to grow. The category includes not only religious texts themselves, but also works inspired by religion, such as those of CS Lewis and even J.R.R. Tolkien. Collectors may focus on the history of a specific religion, or they may build a collection around religions during a specific time period. As religion often influenced (and continues to influence) cultural approaches to art, philosophy, science, and even history itself, a collection based on religion often encompasses books from a number of other subject areas.