While popular nineteenth-century writer F. Marion Crawford’s interest in religion is well-documented, his fiction has been categorised as not carrying overt theological overtones. In contrast to this critical view, this article argues that Crawford’s fiction can be linked to his religious thinking; however, the manner in which his works articulate this interest is non-prescriptive. The article contends that Crawford’s handling of religious dilemmas shapes the unusual generic form of his literary works, in particular Mr. Isaacs (1882). To this end, the article examines Crawford’s mystical position on the Idealism-materialism question that was much debated within theological circles in the nineteenth century. Through an analysis of his non-fiction writings and Mr. Isaacs, I demonstrate how Crawford places ideas from Buddhism and Christianity in conversation to arrive at a “mystical” position on a spiritual “Ideal,” which he defines as an aspiration towards the transcendental that can be partly grasped in reality. As I demonstrate, Crawford draws on this unusual mystical notion of the “Ideal” to develop a new literary form that merges romance with elements from realism in Mr. Isaacs