but it doesnt say that. you paraphrased the book in a way that makes it look sloppy but it was your paraphrased version which is sloppy. if you read through the book when it defines this stuff, it introduces accidentals as "characters that can be placed before notes to raise or lower them" and then in the section on the major scale it says "All major scales use the notes of the musical alphabet in order; no notes are skipped and no notes occur twice." i dont think this is ambiguous