We have a new book available for download from RPGNow: The Tempest by Stewart Wieck. This is an Ars Magica adventure from the olden days -- way back to Lion Rampant olden -- which, I believe, first introduced House Díedne and its dark secret in the Order's past.
This is the one of numerous dusty tomes that will be soon added to our online collection. We recently worked an arrangement with RPGNow and a vendor they found to digitize a bunch of old pre-Atlas Games titles in the Ars Magica line, many of which have long been out of print (like this one, and the original Covenants book published by Lion Rampant in 1989), the digital files of which were lost long ago (before we took over the game). Unfortunately, as with some similar books I scanned and put on RPGNow earlier (such as The Maleficium and Pax Dei), the result of working from hard copy is not as clean as a purely digital distillation. (It doesn't help that some of the oldest books were originally done as camera-ready 300 dpi laser printer output with mechanical paste-up of photocopied artwork...) On the bright side, the folks who did the scanning did run OCR software, the result of which is that you can actually search the text and do similar useful things, which the laborious scanning process I was using myself before didn't do.
Watch this space; as I get more books online, I'll post notice here.