The Complete Guide to Middle earth

The Complete Guide to Middle-earth: from The Hobbit to The Silmarillion is a reference book for the fictional universe of J. R. R. Tolkien's Middle-earth, compiled and edited by Robert Foster.

The Complete Guide to Middle-earth is a major expansion of Foster's A Guide to Middle-earth, which was published in a limited edition by Mirage Press in 1971. Almost twice the length of the original (573 pages vs. 292 pages), the 1978 version incorporates extensive entries related to The Silmarillion (1977). A further revised edition (ISBN 0-345-44976-2) was published in 2001 in time for the The Lord of the Rings film trilogy.

The Complete Guide to Middle-earth is generally recognised as an excellent reference book on Middle-earth. Christopher Tolkien has commended it himself as an "admirable work of reference". However, as it does not include information on post-Silmarillion material (i.e. Unfinished Tales and the series The History of Middle-earth), the 1978 edition contains some assertions contradicted by later publications. For example, the Star of Elendil jewel (Elendilmir) is identified with the Star of the Dúnedain given to Samwise Gamgee, but Christopher Tolkien refutes this. It also includes speculation on matters later confirmed in subsequent works. For example, Foster proposes Gandalf and Olórin are one and the same - confirmed in Unfinished Tales.

A German edition, Das Große Mittelerde-Lexikon, revised and translated by Helmut W. Pesch, was published in 2002.