I'm also glad that I'll now have a chance to read my fellow contributors' essays, which cover a range of subjects from Mesopotamian sources and the Goth/Lombard/Byzantine connection to writers whose lifespans overlapped Tolkien's own like Haggard and Buchan. It's not an exhaustive collection -- it's hard to see how it cd be** -- but it's a good place to start a look at how Tolkien handled his sources (which is as interesting a question as what the sources were).
And of course congratulations to Jason for his first book. Putting together a collection of essays by diverse hands can be like herding cats, and it's a tribute to his organizational powers and stick-to-it-ness that we now have this book. Kudos!
*which I delivered at last year's MythCon in Dallas.
**a thought which conjures up visons of a companion volume someday with pieces on MacDonald, Morris, Dunsany, &c.