An introduction into what the heck BookMaster is would have been helpful. It seems rather odd that you would have used the same name that IBM used for their mainframe based document formatting system way back in the 1980s. Anyone in technical writing from way back will recognize that name and associate it with IBM's GML (General Markup Language) document editor/creator. GML far precedes HTML and ePubs and PDFs. I used IBM BookMaster while working at IBM in the 1980s. I would be very surprised if that name isn't trademarked, so you might be getting a call one day from their legal beagles.