If you’ve never read Tolkien, you may be wondering where the ideal place is to start. Ironically, it’s not at the beginning.
Tolkien began working on the stories that would form the history and mythology of his Middle-earth while still a young man; he even worked on it sporadically as a soldier in the First World War. So those tales, eventually collected posthumously as The Silmarillion, are properly the beginning of the story of Middle-earth.
However, the first of the books to be published was The Hobbit, which is set in the Third Age of Tolkien’s world. (The Silmarillion, including the later portions which deal with Númenor, is mainly concerned with the First Age and Second Age, as well as the vast period before recorded history.)