Christopher Tolkien was born in Leeds in 1924, the youngest son of J.R.R. Tolkien. After service in the RAF in the Second World War and study at Oxford, he became a lecturer in Old and Middle English and Old Icelandic there. He was the first audience for his father's stories, and he drew the maps that appear in The Lord of the Rings, including a redrawn version in the 1970s.
He was not a novelist. His work was editing: sorting a mass of handwritten drafts, many of them rewritten over half-erased earlier versions, and deciding what could stand as a book. After his father's death in 1973 he shaped The Silmarillion, which appeared in 1977, with help from the fantasy writer Guy Gavriel Kay. Unfinished Tales followed in 1980, and then the twelve volumes of The History of Middle-earth, which print the drafts and trace how each legend changed. Later came The Children of Húrin, The Fall of Arthur, Beren and Lúthien and The Fall of Gondolin, along with editions of his father's Beowulf work and The Legend of Sigurd and Gudrún.
In 2016 the Bodleian Libraries gave him the Bodley Medal for bringing his father's literary legacy to the public. He died in France in January 2020, aged 95.
Start with The Silmarillion if you want the foundations of Middle-earth: the creation of the world, the long war against Morgoth, and the stories that The Lord of the Rings looks back on. It reads more like chronicle than novel, so take it slowly. If it feels austere, The Children of Húrin and Beren and Lúthien give single tales from the same history a more focused shape.