A very interesting [treemap](http://radar.oreilly.com/archives/Q206YoYproglangtree.html) from O’Reilly that shows programming book sales in Q2 2006 compared to Q2 2005.

The most striking thing is how diverse the programming language world has become since the start of the decade. Although there were just as many languages in 2000 as today, you heard of little else except VB, Java, C++, JavaScript and maybe Perl. The change has been so dramatic that it even got [noticed](http://blog.intentionalsoftware.com/intentional_software/2005/12/computer_langua.html) by the Wall Street Journal last December.

The quick summary is that the top tier remains C++, C#, Visual Basic, JavaScript and Java. No surprises there except VB’s continued growth. JavaScript is the fastest growing, and as Tim points out, there will be a slew of new JavaScript books and updated editions in the coming months to satiate the Ajax hype.

The second tier made up of Ruby, PHP, Perl, Python and SQL. Surprisingly, they now all have roughly the same market share with PHP being the biggest.

The third tier is made up of a number of other languages, which are unfortunately hard to pick off the graph.

Of course, book market share does not directly translate into actual market share for a programming language. As Tim’s article [points](http://radar.oreilly.com/archives/2006/07/state_of_the_computer_book_mar_4.html) out, a number of other factors can influence book market share and year over year growth numbers.