The "Fingers Of Steel" imprint is a series of books and videos published by Folkcraft Instruments. With over two dozen titles, from some of the best artist/instructors the dulcimer community has, you'll find something that fits your needs.
These titles are sold directly by Folkcraft Instruments. They're also available from the authors, from your favorite dulcimer specialty stores, and from both Barnes And Noble and Amazon.com.
All Fingers Of Steel publications are also available for purchase (in PDF format) atDulcimerDownloads.com.
Here's what's currently in print from the "Fingers Of Steel" catalog: