The 1820s were the great era of the literary annuals. Gift-book album-anthologies, often containing writing commissioned in response to illustrating plates and aimed at a middle-class and mostly female reading public, these collections became a lucrative enterprise and, as Jerome McGann has recently said, constituted in material form what was arguably "the single most important (and institutionally based) poetic genre of the period" ("Rationale of Hypertext: Example D"). They were also important as a venue for short fiction. Annuals typically appeared in time for the Christmas gift-buying season, so that the Keepsake for 1829, for example, would have been published in December 1828.
The Literary Souvenir, Forget Me Not, the Bijou, and as many as sixty-two competitors were available by 1831, according to Peter Manning (p. 44). Among these the Keepsake appeared in late 1827, planned to be the most extravagant, fashionable, and elegant of the annuals. Founded by artist and engraver Charles Heath and William Ainsworth, the Keepsake eventually contained work by many of the most important writers of the day, including (reluctantly) Wordsworth, Coleridge, Hemans, and (posthumously) Byron and Shelley--as well as Mary Shelley.
As Manning points out, Mary Shelley found writing for the new Keepsake a valuable source of income, a necessity for supplementing her 100-pound annuity from Sir Timothy Shelley (p. 55). Around the time she produced The Last Man in 1825-26, and for several years thereafter, while working on other novels, she published frequently in the Keepsake, sometimes making multiple contributions to a single issue. Largely in response to Sir Timothy's strictures, she usually appeared in its pages as "the author of Frankenstein."
See also Sonia Hofkosh's discussion of "the effacements of representation" in Mary Shelley's work during the time that she was writing for the annuals, "writing to make a living, trying to shape a life and a self in the face of circumstances that appear in and through linguistic form, but on her own form as well" (205).