Logic and algorithms are essential to algorithmic Thinking (AT). Humans already have an innate, intuitive understanding of both logic and algorithms. On the other side, they are both mathematical concepts in nature. Consequently, each has its own set of rules, procedures and definitions, which are very precise and systematic. That means we can’t rely solely on our intuition when dealing with these topics, otherwise, we’ll make mistakes. The best way to overcome this is to learn the precise, yet difficult core concepts. Research exists that shows us where newcomers tend to make mistakes (Pane, 2001). This Handbook focuses on elements relevant to getting teachers and/or trainers into the habit of thinking logically and algorithmically. By the end of this handbook, readers will have learned how to apply logic and algorithms to problem-solving. With some practice, they should become second nature.