It really depends on how much technical material there is in the book. Personally, I like using the Nemeth Code so if there is any technical text, I choose to use Nemeth Code. But that is not required. If there are just fairly infrequent instances of technical material, the book can be done in literary code. Technical material in the book for which there are no symbols in literary code or Formats would be transcribed in Nemeth Code with appropriate tn's to the reader and Nemeth symbols listed on the special symbols page, or at the site.