For nearly 300 years, authors of all kinds have expanded the world of Lemuel Gulliver through multiple fifth voyages, spinoffs, mock treatises, verse exchanges, and much more. Close to 200 imitative or supplementary works were produced and reproduced between late 1726 and 1730 alone, and well over 100 in each of the following two decades, the 1730s and 1740s. Most Gulliveriana signals a formal connection with Travels, whether it revisits old settings, fills in perceived gaps in the narrative, or provides additional material. First establishing some common terms and issues in the study of print-based Gulliveriana, this chapter explores the different ways in which secondary writers have filled in and filled out the author-explorer’s world in his name. The final section explores proleptic continuations attributed to Gulliver’s offspring, time-forwarded Gullivers, and other, non-Gulliverian authors.