The idea of school pupils learning to “code” has been widely talked about in recent years, and the media discussions around this idea have almost redefined what we mean by “coding”. We can see increased public interest in coding by simply counting Google searches on the phrase “learn to code”, which increased rapidly from 2011 (shown by the black line in Figure 1.1), when industry, governments, and media started talking about this being an important aspect of children’s education. Traditionally this skill might have been referred to as “computer programming”; the grey line in the figure shows the corresponding number of searches for “learn to program”, which is being searched less often (relatively) over time.