How do I punctuate parenthetical citations that include an author’s name and “introduction”?
Separate the items with a comma:
You Must Change Your Life is “a portrait of two artists fumbling through the desultory streets of Paris, finding their paths to mastery” (Corbett, introduction).
Corbett, Rachel. You Must Change Your Life: The Story of Rainer Maria Rilke and Auguste Rodin. Kindle ed., W. W. Norton, 2016.