Instruct: Classify an Amazon review into positive or negative sentiment.
Query: Not up to par with other Schaum's outlines on mathematics

This is one of the more poorly written Schaum's outlines I have encountered. The theory is very murky and the author gives no clear direction as to where he is going with this material and what it all means. PDE is a hard enough subject without working a bunch of meaningless problems that leave you wondering what it is you are supposed to have learned. Instead, I suggest you read "Introduction to Partial Differential Equations with Applications" by Zachmanoglou and Thoe in order to understand the mathematical underpinnings of PDE. Then read "Partial Differential Equations for Scientists and Engineers" to get a thorough feel for how PDE is used to solve real-world problems. Both books usually sell used for under $10 each, making them cost-effective alternatives to this Schaum's outline.