This book summarizes the work Scott, Fuller, and their team of scientists conducted over 20 years on 5 breeds of dogs. Before their work, American psychology had been very dominated by learning theory and tilted very much toward nurture in the nature-nurture (instinct vs. learning) debate. The work of the European ethologists such as Lorenz & Tinbergen on "critical periods" in early development had little impact until the studies (summarized here) of the Scott & Fuller group began appearing. Their careful scientific work demonstrated the importance and existence of time limited phases in the early life of dogs within which certain experiences need to occur or the dogs may be forever deficient. Their work (with that of Eckhard Hess's on ducks and geese) demonstrated that these critical or sensitive periods in early development could be scientifically studied in ways compatible with a scientific psychology.
The book is important to those interested in the history of behavioral sciences since the discoveries are applicable to many species (including humans) and not just the dog.
This book will always be especially valuable to dog breeders and trainers; its last chapters summmarize in very clear terms the particular phases in early development and experiences the dog needs to be adequately socialized. The reader can refer back to earlier chapters to get more information on how the experiments were conducted and the distribution of results. It answers questions on proper age that puppies can be separated from their mothers, what experiences are important to provide at what age, etc.