This book seems like it would work for an intro class to GIS anywhere from the middle school to the college level (I used it for a graduate level intro course). For the most part, it does a good job introducing broad, central, concepts in GIS without getting too technical or bogged down with detail.
That being said, it also doesn't offer a whole lot to sink your teeth into. Some of the parts are painfully outdated, too. After reading some of the stuff about the advent of the new fandangled world-wide web, I had to check the copyright date. AOL?? Really? I also felt like it did a bad job introducing database concepts. Regardless of these flaws, it does work as an intro text. I am now on the 'Thematic Cartography and Geovisualization' text in the series, and I'm hoping it will be a little more useful.