The Pure and the Impure is a study, or meditation, on key concepts surrounding sexuality: gender, purity, and conventionality. Interestingly, Colette suggests that the term purity has no true meaning for her, saying that:
βThe word 'pure' has never revealed an intelligent meaning to me. I can only use the word to quench and optical thirst for purity in the transparencies that evoke it - in bubbles, in a volume of water, and in the imaginary latitudes entrenched, beyond reach, at the very center of a dense crystal.β
In the text, Colette presents a number of case studies to us, all of which focus on a particular person. She calls these subjects "restless ghosts unrecovered from wounds sustained in the past when they crashed headlong or sidelong against that barrier reef, mysterious and incomprehensible, the human body." Through these characters, Colette reveals differing perspectives about the themes of the texts, giving us an insight into attitudes about gender and sexuality at the time she was writing.