Macmillan’s Magazine has long been recognized as one of the most significant of the many British literary/intellectual periodicals that flourished in the second half of the nineteenth century. Yet the first volume of the Wellesley Index to Victorian Periodicals (1966) pointed out that ‘There is no study of Macmillan’s Magazine’ - and that lack has been only partially remedied in all the decades since. In this work, George Worth addresses five principal questions. Where did Macmillan’s come from, and why in 1859? Who or what was the guiding spirit behind the Magazine, especially in its early, formative years? What cluster of ideas gave it such coherence as it manifested during that period? How did it and its parent firm deal with authors and juggle their periodical work and the books they produced for Macmillan and Co.? And what, finally, accounted for the palpable decline in the quality and fiscal health of Macmillan’s during the last 25 years of its life and, ultimately, for its death? Worth includes a treasure trove of original material about the Magazine much of it drawn from unpublished manuscripts and other previously untapped primary sources. Macmillan’s Magazine, 1859-1907 contributes to the understanding not only of one significant Victorian periodical but also, more generally, of the literary and cultural milieu in which it originated, flourished, declined, and expired.