I had the same initial reaction to the idea; however on second thoughts it actually sounds like an interesting book for someone like me that is stuck with a PHP, Python, C/C++ background.

It would be nice to touch briefly on 7 other, very different, languages (especially Scala and Ruby) and see what they taste like.

So, yeh; I reckon this would be a good book for an already proficient programmer to pick up the beginnings of a few new languages.