The role of play in child development is a source of ongoing interest and debate. In this book, renowned expert Peter Smith offers an expansive definition of the term “play”, taking an in-depth look at its impact on children, as well as its adaptive value for birds and mammals, including primates.

5 Downloadable GRE CAT Exams
The GRE is only administered on a computer, in a format referred to as the CAT (an acronym for Computer Adaptive Test). The CAT is so named because it adapts to your performance question to question. Our 5 practice GREs use a computer adaptation system, like the real GRE exams.

The Astronomy Encyclopedia (2002)
With more than 3,000 alphabetically arranged entries and 500 stunning color and black-and-white photographs, star maps, and diagrams. The Astronomy Encyclopedia covers everything that the general enthusiast--and the more serious researcher--would want to know about planets, stars, galaxies, and our universe. Here is concise, reliable information on the whole field of astronomy, ranging from adaptive optics and cold dark matter, to Islamic astronomy and the lens defect known as vignetting

Attention, posters who are going to post new materials.
Please read comments inside!