The current issue of Therya includes a number of papers honoring the legacy and notable contributions of Dr. Sydney Anderson (1927-2018) to Bolivian and Neotropical mammalogy. “El Doc,” as he was warmly referred to by hordes of Bolivians scientists and students, was as a towering example of an unassuming mammalogist who loved and honored his science so much that he enjoyed camping and trapping in remote areas of Bolivia for almost three decades, and until he was well into his late 60s.

His single-most important contribution to Bolivian and Neotropical mammalogy was his “Mammals of Bolivia, taxonomy and distribution” (^{Anderson 1997}). This monumental monograph has been recognized as the fundamental pillar of contemporary Bolivian mammalogy (e. g., ^{Tarifa 2014}). Significantly, in order to clarify issues such as species boundaries, distributions, and other aspects of taxonomy and systematics to be included in that monograph, Anderson and numerous collaborators published on several taxa also present in neighboring countries. See an overview of Syd’s academic career and contributions in ^{Gardner et al. (2020}). We started planning this special contribution to Therya in mid 2019. At the time, the last draft of the updated and annotated checklist of the mammals of Bolivia (^{Aguirre et al. 2019}) was circulating among the authors, and we had yet not heard of Anderson’s passing. While completing that work, we could not fail to be impressed by the magnitude of Anderson’s contributions to Bolivian mammalogy. When we learned of his death, we immediately began planning a Festschrift in his honor. We drafted an invitation and sent it to over 70 potential contributors in late 2019. We targeted several groups of authors, from people who had worked with him at the American Museum of Natural History to Latin American scientists who had directly worked with him over the many decades of his active career. People also were free to invite any potential collaborators. We received positive responses from about 55 potential contributors. Then, the COVID-19 pandemic happened and several promised manuscripts never materialized. We think Syd would have approved of selecting Therya, the official journal of the Mexican Mammal Society, as an ideal venue for the publication of this memorial for several reasons: Anderson’s interest in and support for Latin American mammalogists, their societies, and their development were patent throughout his life. In addition, he published extensively on Mexican mammals. We are pleased with the selection of papers that are included in this special contribution as well as with the range of topics encompassed: we think they are a fitting homage to Anderson’s efforts in the development of Bolivian and Neotropical Mammalogy.

Finally, we cannot close this editorial without mentioning Justine ^{Anderson. Syd acknowledged her in his Mammals of Bolivia (Anderson 1997}: 5) as “My wife, friend, field assistant, and photographer”, but for those of us that spent time with them in the field (yes, Justine was there too!) it was clear that Syd and Justine were a team! Justine passed away early this year. We are proud to have known, worked, and learned so much from both of them.