Dr. Karl P.N. Shuker BSc PhD FRES FZS is a zoologist who is internationally recognised as a world expert in cryptozoology (the scientific investigation of mystery animals whose existence or identity has yet to be formally ascertained), as well as in animal mythology and allied subjects relating to wildlife anomalies and inexplicabilia. He obtained a BSc (Honours) degree in pure zoology at the University of Leeds (U.K.), and a PhD in zoology and comparative physiology at the University of Birmingham (U.K.). He is now a freelance zoological consultant and writer, living in the West Midlands, England.
Karl Shuker is one of my favourite cryptozoologists, whose blog Shuker Nature I read religiously. He is first and foremost trained as a regular zoologist with an interest in unknown or rediscovered species, who also shows an indepth enthusiasm for the folklore surrounding mythical beasts, and hence works with a level of scientific methodological rigour that is without parallel in the field. His knowledge of folklore across the world and sense of humour are of a very high level as well.
This book is not just a good introduction to mysterious cats seen around the world, with the "alien big cats" of his native Great Britain taking the lion's share (sorry couldn't resist the temptation to make that pun) of the page space. It is also a good introduction to the basic biology of big cats and the history of their proliferation across the world through history that most laypeople are probably unfamiliar with. I was surprised to learn how many big cats did in fact inhabit much of Northern Europe including Britain during the Pleistocene. As a matter of fact I came away from having read this book more convinced than ever before that Britain today might have breeding populations of jaguars, leopards and pumas that have escaped from private menageries of exotic animals that have been popular among the British upper class since the 16th century.
The chapters about the rest of the world, especially the Americas, are also worth reading and make a good case that most mysterious big cats around the world can be easily explained as either out-of-place occurrences of existing species or rare mutations of well known big cats rather than completely new animals. This book is basically a perfect example of how to do cryptozoology as the study of unknown animals taken literally.