Cats in Australia. Companion and Killer. Woinarski, J. C. Z., S. M. Legge, and C. R. Dickman. 2019. CSIRO Publishing, Clayton South, Victoria 3169, Australia. viii + 333 pp. AUS$59.99 (paperback). ISBN 978-1-4863-0843-9. Cats and Conservationists. The Debate over Who Owns the Outdoors. Wald, D. M., and A. L. Peterson. 2020. Purdue University Press, West Lafayette, IN, U.S.A.. viii+ 152 pp. US$19.99 (paperback). ISBN 978-1-55753-887-1. For over 4000 years, the domestic cat (Felis catus) (hereafter cat) has been our companion and live-in rodent catcher. Where we have gone, cats have usually gone too, including the Americas and Australasia. However, pet cats have the capacity to become feral, after which they can increase and spread without further human assistance. And although we have taken the cat out of the wild, we have not taken the wild out of the cat; even pet cats kill millions of small mammals, reptiles, and birds each year. This dual identity as pet and feral predator makes managing cats to protect indigenous wildlife both more difficult and more contentious than managing other introduced predators. The 2 books that are subject of this review, Cats in Australia and Cats and Conservationists are, respectively, about the effect of cats on Australia's indigenous fauna, and how to resolve, or at least moderate, the debate between cat advocates and wildlife conservationists. I found the first to be a far more important and useful book than the latter. Indeed, Cats in Australia contains so much information on cats and their impact on Australia's indigenous fauna that it should be essential reading for conservationists, wildlife managers, and cat lovers, especially those on that continent. The book has 12 chapters (plus a conclusion) that cover a comprehensive range of topics, including the origin and natural history of cats; their interactions with other predators; their impacts on biodiversity, both globally, and specifically in Australia; their spread, distribution, and population size in Australia; cat management methods; laws and policies pertaining to cats; ethical considerations about cat management; and community attitudes to cats. I am pleased that the authors did not use text boxes, a device I find does not make books any easier, or quicker, to read or useful information easier to locate. Although a short bullet-point summary at the beginning or end of each chapter would have been useful, key information is effectively summarized in graphs, maps, and tables. All chapters are well-written and informative but chapter 6, “Impacts of Feral Cats on Australian Wildlife,” and chapter 9, “Management of Cats in Australia,” are perhaps of the most interest for, and benefit to, wildlife managers and ecologists. The stand-out feature of this book is simply the collection in a single volume of a vast amount of information previously only available in disparate publications. Not only have the authors done an excellent job of compiling this information, they have also done an excellent job of organizing and presenting it. I found no evidence in Cats in Australia of the “Moral Panic over Cats” alluded to by Lynn et al. (2019), who argue that those who oppose the lethal control of cats for conservation have been unjustly labeled “science deniers,” akin to those who deny climate change or the dangers of smoking. The authors of Cats in Australia are well aware that killing cats may not always be necessary, or even desirable, and recommend that it be undertaken only when there is good evidence that it will benefit native species. Indeed, they discuss alternatives to killing cats, such as habitat modification and fencing, in considerable detail and provide some interesting examples of cases when killing cats actually made things worse for native species. The risks associated with controlling just one of a suite of predators, such as mesopredator release, are hardly unknown in ecology and conservation (King et al., 1996). In New Zealand, at least one eminent ecologist has argued that suburban pet cats could actually benefit native bird species by suppressing introduced rodents and mustelids (Flux, 2017) and has not, to the best of my knowledge, been labeled a science denier. However, just as the authors of Cats in Australia are well aware that controlling cats may not always benefit native species, they are also aware of the risk of assuming that an ecological equilibrium has been reached between cats and native fauna. The authors present strong evidence that this is not the case for many indigenous Australian species. Cats and Conservationists focuses on the acrimonious debate between cat advocates and conservationists in the United States about the effectiveness of the trap, neuter, and release approach to managing stray and feral cat populations. It is a sociological, rather than ecological, book composed of 4 chapters (plus an introduction and conclusion) entitled “The Cat Problem,” “The Science Problem,” “The Values problem,” and “The Social Problem.” I found this book rather unsatisfying. Although the authors discuss the debate in detail and advocate “philosophical pragmatism,” “…a kind of ethical empiricism in which moral judgement is inseparable from empirical knowledge,” as a means of resolving it, they have not actually implemented this. They stop at merely recommending that both sides employ evidence-based decision-making, listen to the other's point of view, seek common ground, and refrain from name-calling, all of which I would have thought were fairly basic to civilized discourse. I highly recommend Cats in Australia to anyone interested in the ecological impact of cats on Australia's indigenous fauna and the ethical-philosophical debate over killing cats for conservation purposes. Because of its much narrower focus and sociological, rather than ecological content, Cats and Conservationists will be of more limited appeal, but will still be of interest to those engaged in the cat debate. Cats in Australia left me with a rather sober appreciation of the scale and scope of the issues, whereas Cats and Conservationists highlights the acrimonious politics that complicate managing cats for conservation. As the human population increases, so does that of our pets. The idea that cats will eventually reach an ecological equilibrium with native species overlooks this continual growth in the global cat population. If the planet can be overpopulated by humans, it can also be overpopulated by cats. Perhaps an indication that this has already happened is the discovery that the parasite Toxoplasma gondii, of which cats are the only known definitive host, is now a significant cause of mortality in New Zealand's endangered Hector's (Cephalorhynchus hectori hectori) and Maui (C. h. maui) dolphins (Roberts et al., 2020). It boggles the mind to think of the amount of cat feces that must be going into the sea to infect these rare marine mammals with toxoplasmosis. Under these circumstances, I think we should increasingly give the benefit of doubt to endangered species, not cats. After all, as a colleague of mine once observed, “They're still making cats.”