For technical references it's a very sad day if the only thing I can find is a PDF or ePub. It hasn't happened yet. Technical references aren't read sequentiall

For technical references it's a very sad day if the only thing I can find is a PDF or ePub. It hasn't happened yet. Technical references aren't read sequentially; random access is essential. By far the best technology available for random access is a book. Web browsers are a close second, but only if the content has been formatted specifically for the web.