Short answers, pulled from the story.
J. R. R. Tolkien (1892, 1973) was an English Roman Catholic writer, poet, philologist, and academic who spent much of his career as a professor of medieval English at the University of Oxford.
Tolkien followed earlier authors like William Morris and James Macpherson by using devices such as archaic prose styles, elegies, historical appendices, forged manuscripts, maps, and calligraphy to create a feeling of realism. He constructed languages, genealogies, and histories to provide inner consistency that commands Secondary Belief and prevents disbelief.
Tolkien used his pipe to burn the edges of the Book of Mazarbul pages, pierced holes along one side to resemble stitching, and washed them with red paint to resemble bloodstains. These methods enlisted the aesthetics of antiquarianism and adopted the techniques of literary forgery to support the story.
Tolkien began making maps depicting Middle-earth early in his writing process to help with plot development and contribute to the impression of depth and realistic worldbuilding. He drew maps such as the one of Gondor and Mordor to scale on graph paper, plotted protagonists' tracks, and annotated these with dates to ensure chronology fitted exactly.
Tolkien stated that he is a philologist and all his work is philological, meaning his stories were made rather to provide a world for the languages than the reverse. The invention of languages like Quenya and Sindarin was the foundation, where names came first and the story followed.