I am a big fan of Tool's music, but I have to admit that I have not gone out of my way to read in to their music. I like to make my own impression of the meaning of a song, as it's true, that people take different things from a song dependent on their emotional state and musical understanding.
Therefore, for me, as some not overly well read on all things tool, this covers some decent aspects of their beginnings, and the development to where they are today, albeit, not in huge granular detail. I think there is a good broad scope of information here, but am improved level of detail at many stages would have made this an altogether more complete read. I agree with another reviewer that it is clear that the author has not had much access to the band, if at all.
If you know a lot about the band, there is probably not much new material here for you, but if you have little background, this is a fairly decent read.