Building Thinking Skills
This is a very complete thinking skills program, covering all of the figural and verbal skills your children are likely to see on a standardized test. The publisher, Critical Thinking Press, states that Building Thinking Skills is "designed to significantly improve verbal and figural skills in four important areas: similarities and differences, sequences, classifications, and analogies. Proficiency in these skills is the cornerstone of success in all academic areas, on standardized tests, and on college entrance exams." They have scads of testimonials documenting the correlation between use of this series and increased test scores. We have no doubt that all the practice you get in using this series would, indeed, improve test scores. More importantly, many of the specific skills practiced here also have application in different professions. Other skills would seem to generally improve your ability to "see things" in different ways or train your mind to stretch in different directions.
The broader goals of this series are translated into specific skills and exercises within these areas. Learning is spiral within skills, within books, and between levels. That is, exercises progress in sophistication and scope within each book, and from level to level. This translates into several hefty worktexts full of practice exercises that children actually enjoy doing! Except for the Primary level, students can work pretty much on their own, proceeding as quickly through the series as they're able. If you're starting an older child in the series, however, use the suggested grade levels for proper placement.