Martinez is a popular commentator on J.R.R. Tolkien and Middle-earth. His Web book, Parma Endorion: Essays on Middle-earth, was published in 1996 and revised in 1998. Thousands of teachers, students, and librarians around the world have praised the book and used it as a resource for term papers and dissertations.

The author also writes a weekly column on Tolkien and Middle-earth for Suite101.Com. A large part of the content for Visualizing Middle-earth was derived from Suite101 essays written in 1998 and early 1999.

Now, in the wake of several changes in Xlibris' program for self-publishing, Martinez has announced he will sever his relationship with the publishing services provider later this year. Visualizing Middle-earth was offered as an experiment, and it has proven to be successful. The book has earned critical praise within the Tolkien community.

Martinez explains why he will leave Xlibris as soon as his current promotional campaigns have finished. Self-publishing was a reasonable option for Visualizing Middle-earth because the essays had already been published. And at the time Martinez contracted with Xlibris to publish the book, he was able to take advantage of their free core services program. Xlibris is no longer publishing books for free.