The first edition was a two-volume set
Christina Scull and Wayne G. Hammond have announced that a second edition of their J.R.R. Tolkien Companion and Guide will be published next year.
The Companion and Guide is a comprehensive work of reference on J.R.R. Tolkien, comprising an extensive detailed Chronology and an encyclopedic Reader’s Guide.
It is an unrivalled collection of information on the life and works of J.R.R. Tolkien based on sources unavailable to most researchers.
The second edition will correct and revise the original text, with the Reader’s Guide expanded and split into two volumes.
The three-volume second edition of The J.R.R. Tolkien Companion and Guide is due to be published 7 September 2017.