A background in the history surrounding the craft can help show what fundamentals are key even as the means of production changes. "Teach Yourself The Art of Music Engraving & Processing" by Ted Ross covers the background of music reproduction. It then follows the procedure from preparing the music to notations to examples. The original 1987 edition has been updated with a CD-ROM in 2001.
Musical notation is one of the most important skills needed to reproduce music. The smallest details in a piece need to be accurately conveyed to all the parts. Coursework in this is often included in traditional music schools. One book cannot provide all the training needed in this field, but a good starter is "Music Notation (Berklee Guide" by Mark McGrain. It is touted as a resource for handwritten compositions and for use with music software.
Once you understand the whys and hows of musical notation, this knowledge needs to be applied to computer programs. One book to get started with is "Music Engraving Today" by Steve Powell. The 2007 edition shows how to apply the rules of music engraving to computer programs Finale and Sibelius. It also covers different types of music to be produced, such as music for books and commercial copywork. Music fonts, another important aspect of engraving, are also covered.
To reproduce music today, computer programs can quickly produce results that took much longer by hand years ago. A keyboard plugged into the computer makes things much easier. A software package called Finale is one of the most common today. The company says that over 2.5 million professionals and amateurs use its software. Many resources exist to teach the fundamentals of the software, including "The Finale Primer: Mastering the Art of Music Notation with Finale" by Bill Purse.