I had never studied business before (at any level), but found myself in a position where I was managing software projects, and dealing with MBA's from our client companies every single day.

I wouldn't say this is a replacement for going to business school, but for me -- it helped me understand the world my clients were coming from, and how they were incentivized.

So yes -- very practical book, easy to get through, and highly recommended. Gives a broad overview of the field, so you can at least speak the lingo.