This is a great set of books by Donald J. Sobol, who also gave us the incomparable child-detective, Encyclopedia Brown. These books are published as both a compendium volume and as separate books by Scholastic, and have been in print since 1967.
Each book contains a number of one or two-page scenarios setting up a puzzling mystery. The reader is given the opportunity to solve the mystery using general observation skills and common knowledge. These books are not merely great brain-teasers, however. They provide excellent training in detailed observation as well as making use of what seems trivial knowledge. For example, in one mystery, a young man is trying to impress his animal-loving, equestrienne date by telling her how his prospector uncle took great care of his pregnant mule. The young lady, of course, ditched him as a liar. Why? Because mules are sterile, of course.
Great for kids or adults, these books are also quite convenient to read. The shortness of each mystery makes these great “waiting in line” reading, or just before bed brain-teasers.
It should be noted that some of the mysteries are somewhat dated, especially those dealing with fashion or with traveling by train; however, these installments may be used to provide some historic insight into the daily life and habits of those who lived in earlier decades.