The J. R. R. Tolkien Companion and Guide is a 2006 reference book by the husband and wife team of Christina Scull and Wayne G. Hammond.

In his opinion, "the breadth of the coverage and the authority with which Scull and Hammond document Tolkien's life and times will make these books an invaluable supplement to Humphrey Carpenter's classic 1977 biography and their own 2005 The Lord of the Rings: A Reader's Companion.

Where there is interpretation beyond what Tolkien or his son Christopher write, the work tends to cite scholars like Verlyn Flieger and Tom Shippey.

[2] Jason Fisher, also writing in Tolkien Studies, notes that early reviewers were correct to predict the "lasting value" of Scull and Hammond's work, calling it "an indispensable resource" alongside the pair's other books, especially "for matters of biography and bibliography."

He notes, too, that the work has been greatly expanded, incorporating years' worth of material on the authors' website.