"A combination of circumstances means that we know more about J.R.R. Tolkien than about almost any other author, from any period. Nevertheless, in spite of all the efforts, there remains a certain opacity about Tolkien, both professionally and personally.
As this book shows, there is a way to bridge that gap which has not been previously attempted: a fact which makes this work by Oronzo Cilli arguably the work with most potential for giving us a truer understanding of Tolkien; a work which, besides its own immediate effect, points the way for many further studies. What Oronzo has done is, quite simply, to collect what is known about the books Tolkien owned and read.
The best guide to an author's mind is through his books, and in the work of Oronzo Cilli we have now the best and most valuable guide to Tolkien's books. It is a devoted, enduring, and above all inspirational work of scholarship, but not, as Oronzo knows, a final one. It joins that very select group of works, the most useful of all: a book we should keep, update, and write notes in the margin of, for the rest of our lives."
Tom Shippey