Deep Reader was a viewer for Palm "doc" files on PalmOS PDAs. It was developed by Zane Rutledge. It featured custom fonts, anti-aliasing, smooth scrolling, and special support for hi-resolution devices like the HandEra 330 and Sony Clie.
Deep Reader's last version was a beta released in 2002, and it appears to have been abandoned by the author. Zane is involved in film making and games development -- his PalmOS game Edge won a $10,000 prize -- and he seems to have long since lost interest in the reader.
The reader is still available here for those interested in history: http://www.rzanerutledge.com/deepreader/