I fail to understand the poor reviews of this EXCELLENT introductory text on mathematical modelling.  Practitioners of mathematics are known for their masochistic love of proofs and rigor, and when covering more advanced concepts, authors of mathematics textbooks make the mistake of assuming that their audience is versed in high-level mathematics (because who else would they be reading an advanced mathematics textbook, right?).  However, I research for a living, and my job requires that I master many areas of knowledge quickly and efficiently despite the fact that my quantitative skills are not the best.  Therefore, I have mastered the ability to find references that sufficiently cover advanced concepts in a seemingly oxymoronic basic and accessible manner.  Such books are rare, but this is precisely what the author has done in this instance.  Having reviewed many, MANY books on Mathematical modelling, the subject matter simply does not get any easier or clearer than this.  In my opinion, if the reader cannot grasp the concepts laid forth so plainly in this AMAZING textbook, then they probably should not be pursuing a major that requires any mathematical modelling at all.  Kudos to the author.  I hope to see more good work like this in the future.