Jason Fisher has done an admirable job editing this collection of essays (he is also a contributor). This book remains the single best essay collection on Tolkien's sources. If nothing else, you should buy this book for the contributions by topnotch scholars Tom Shippey (author of The Road to Middle-earth & Tolkien: Author of the Century), John D. Rateliff (editor of the two-volume History of The Hobbit), and Diana Pavlac Glyer (author of The Company They Keep). All three of these writers have received the Mythopoeic Scholarship Award for their books.
There are a number of other articles by lesser known Tolkien scholars, but they are just as interesting and astute. Beyond the three mentioned above, my personal favorites were Kristine Larsen's "Sea Birds and Morning Stars," and Thomas Honegger's "The Rohirrim: 'Anglo-Saxons on Horseback'?"
The one criticism I have of this collection is I wish that it was a bit longer--I personally would have liked to have seen at least one contribution from the editors of Tolkien Studies (Anderson, Drout, Flieger). And, of course, there is still much more to be said about Tolkien's sources--this book doesn't pretend to be exhaustive (is any book?), but it remains a worthwhile contribution to Tolkien studies in particular and source study in general.
I highly recommend this book to general readers and libraries alike. If you like books about Tolkien and his fiction, this is a must have and must read. It is multifaceted enough for everyone to find something enlightening, thought-provoking, or compelling. I, for one, found all three.