Prose craft
Tone
The writer's attitude toward the subject matter and audience, built from diction, syntax and detail: how the narration feels about what it says.
The tone of a literary work "expresses the writer's attitude toward or feelings about the subject matter and audience." Tone is built sentence by sentence, through diction, syntax, imagery, the details included or omitted, and figurative language; a smug character is made smug by words like "surveyed" and "snatching." The classic confusion is with mood: mood is the atmosphere the work produces in the reader, generated through setting, theme, voice and tone together, while tone is the attitude above the sentence. Tones range from formal to whimsical, solemn, ironic or threatening, and may shift across a work; the word itself was borrowed from music.
For novelists tone is a register decision with a reader contract attached, and an unplanned collapse from the elevated to the trivial is bathos. The stable component readers learn to recognize is the writer's voice, which criticism assesses by tone, style and personality.