Books are useful sources for a number of reasons. Old books offer a window onto another era by compiling information or presenting topical subjects of the day. Moreover, they tell us a great deal about the time in which they were published, along with the preoccupations of their authors and society in general. Recent books are also important because often they are the simplest way of transmitting the knowledge and interpretations of other historians, folklorists or authors on a given subject.
There may be many reasons behind the writing and publishing of books and brochures. Some authors hope to make money, while others write for social or educational purposes. As for the books and the collections of legends presented here, what motivated their authors was a fascination with the mystery surrounding Jerome.
Historians must always keep in mind the influence that authorial intention has on the content of books. The fact that a source is printed is no guarantee of veracity or accuracy. Like any other type of source, such as letters, diaries or unpublished government documents, books must be analyzed critically, for opinions and intentions are not always explicit and authors can make mistakes. Consequently, a description of an event is just one element that must fit together with other elements before we can be certain that an event happened as reported. The Jerome legend has been repeated so often that the original version is almost unidentifiable.
Books are generally classified by title and author, so the process of research is the same regardless of the particular library, except in the case of school libraries and small public libraries, which are likely to hold few old books. Works dating from the 19th and early 20th Centuries are fragile and often rare, which is why large libraries sometimes keep them in a reserved section called “Special Collections”.