The fluidity of adolescent identity, which itself could be viewed with anxiety or even outright suspicion in mid-Victorian society, creates fascinating and informative tensions within the novels of George Meredith, W. M. Thackeray, and Anthony Trollope. The focus of each author on male adolescence as a transient, formative stage of development on the one hand, but as a separate masculine type or identity with its own characteristics on the other, has as yet received limited critical attention despite its prominence and recurrence in their fiction. Adolescence is often constructed throughout the mid-nineteenth century by a range of discourses as a fluid period of formation, in which appropriate masculine values may be learned. The chapter also presents an outline of the book. The book involves a reassessment of the work of these three authors who, as established novelists, repeatedly chose male adolescence as a primary subject.