The fourth book, Tribute of Death, has had to be self-published due to insufficient sales of the previous books, despite critical acclaim. If you like this series and want to see more, Simon Levack's website gives the following tips:
Buy my books (well, you were expecting that!)Tribute of Death is available to buy or download from lulu.com.
Borrow my books from your library - and if the library doesn't have one, request it!
Encourage your friends to read my books
Write about my books in your blogs, newsgroups and discussion lists
Get your reading groups to discuss my books
If you know any publishers, booksellers or anyone else who may have a commercial interest in what I've done, tell them about it!
Give this website address out to anyone who may be interested.