Recounts the life of Balto, the sled dog who saved Nome, Alaska in 1925 from a diphtheria epidemic by delivering medicine through a raging snowstorm.

A young woman and her husband are glad that they gave a stray kitten a home when it saves their lives by alerting them to a gas leak.

Babe the pig gets into mischief when he tries to help out with chores on the farm.

This book presents some quasi-experimental designs and design features that can be used in many social research settings. The designs serve to probe causal hypotheses about a wide variety of substantive issues in both basic and applied research. Each design is assessed in terms of four types of validity, with special stress on internal validity. Although general conclusions are drawn about the strengths and limitations of each design, emphasis is...