In software, experience is one of the most valuable assets an engineer could have. An experienced engineer builds a list of tools.
My goal is to help provide guidance on the general issues with maintaining an application. Regardless of the programming language or operating system, the approaches to a wide breadth of problems are very similar.
This book can be read front to back, but is designed to be helpful for specific needs. How do I improve CPU usage? How do I determine the issue with a running application. This books aims to answer those questions.
You'll note that many of the individual section are brief. That is by design. The goal is not to explain every specific technical detail: the goal is to provide guidelines to enable the reader to find the right tools themselves.