For those who have an interest in further reading I would personally recommend the work of the following authors:

Dr John Bradshaw; Bristol Veterinary School; University of Bristol.

Current research concerns the evolutionary psychology of the pet-owner bond, including studies of anthropomorphism.  Also involved as an advisor on a number of research projects in the Animal Welfare and Behaviour Group, including the welfare and behaviour of working dogs, and applied cat population dynamics.  

Dr Ian Dunbar; Sirius Dog Training, USA

Veterinarian, animal behaviourist, and dog trainer, Dr. Ian Dunbar received his veterinary degree and a Special Honours degree in Physiology & Biochemistry from the Royal Veterinary College (London University) plus a doctorate in animal behaviour from the Psychology Department at UC Berkeley, where he researched the development of social hierarchies and aggression in domestic dogs.

Dr Karen Pryor; Karen Pryor Clicker Training, USA

Karen Pryor is a pioneer in ethology and behaviour and the leading spokesperson for clicker training. Karen is a scientist with an international reputation in two fields: marine mammal biology and behavioural psychology. Through her work with dolphins in the 1960s, she developed modern, force-free animal training methods. 

Dr Stanley Coren, University of British Columbia

Though best known to the public for his series of best-selling books on dogs, Stanley Coren is also a well-respected scientist and Professor of Psychology at the University of British Columbia.  He did his undergraduate work at the University of Pennsylvania and completed his doctorate Psychology at Stanford. In addition to being a psychologist and researcher, Coren's life is filled with dog-related activities and he is also an instructor with the Vancouver Dog Obedience Training Club.

Dr Patricia McConnell,  McConnell Publishing Ltd, USA

Patricia McConnell, Ph.D., a Certified Applied Animal Behaviorist, (CAAB) has made a lifelong commitment to improving the relationship between people and animals. She is known worldwide as an expert on canine and feline behaviour and dog training, and for her engaging and knowledgeable dog training books, DVDs and seminars.  Patricia has seen clients for serious behavioural problems since 1988, and is an Adjunct Professor in Zoology at the University of Wisconsin-Madison.  

Dr. Brian Hare  Associate Professor of Evolutionary Anthropology, Duke UniversityDr. Brian Hare is associate professor of evolutionary anthropology at Duke University in North Carolina and a member of the Center for Cognitive Neuroscience, which is a division of the Duke Institute for Brain Sciences. He received his Ph.D. from Harvard University, founded the Hominoid Psychology Research Group while at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and subsequently founded the Duke Canine Cognition Center when arriving at Duke University.

Ken Ramirez; Ken Ramirez Training & Consulting; Shedd Aquarium, Chicago, USA Ken Ramirez, the executive vice-president of animal care and animal training, develops and supervises animal care programs, staff training and development as well as public presentation programs for the entire animal collection at Chicago’s Shedd Aquarium.  Ramirez is a biologist and animal behaviorist who served nine years at Marineworld of Texas He began his training career working with guide dogs for the visually impaired and has maintained a close affiliation to pet training . 

Dr. Sophia Yin, Animal Behaviorist Dr. Sophia Yin is a veterinarian, applied animal behaviourist, and the author of many books and textbooks. Her thesis and related publications were on vocal communication in dogs. Dr. Yin is also on the executive board for the American Veterinary Society of Animal Behavior and was on the American Association of Feline Practitioners’ (AAFP) Handling Guidelines Committee.

Turid Rugaas Turid Rugaas owns and run "Hagan Hundeskole" (dog school) in Norway and works with dogs full time.  She started out training her own dog and competed in  obedience and working dogs and worked with rescue dogs.  She and a colleague started charting the calming signals in dogs and in 1992  went to Canada to the big Animals and US conference, met and got acquainted to a lot of dog trainers and several of them showed a lot of interest in the project with the calming signals.