In this second installment we look at computer book sales in specific technology categories.

Remember that we’ve organized the data into six “Category Families” — Systems and Programming, Web Design and Development, Business Applications, Digital Media Applications, Consumer Operating Systems and Devices, and Computer Topics.

Within each of these Families are category group, super-category, category, and atomic category, in a five-level hierarchy. For example, Systems and Programming includes the category groups programming languages, databases, software engineering, general programming, security, and so on.

In the rest of this post, we will contrast 2011 with 2010.

As a refresher, here are two treemaps of the Category Families, with their sub-areas for the final quarters of 2011 compared to 2010. The map on the left shows the growth of the count of titles in each area and the map on the right shows the growth in units for each area.