Mark Twain often transgressed the sexual limits of his Victorian era, pushing the boundaries of sex and sexuality in his writing. Although he generally was more reticent in his public writing, deferring to the taste of his age, he had private writings that explored sexual and taboo topics. Throughout his writing career, he played with themes of cross-dressing, often couched in comedy, but revealing an interest in the fluidity of gender roles. In his later unpublished writings, he wrote more frankly about sex and sexuality, topics that clearly fascinated him.