The book is called an introduction to computational problem using Python and that is exactly what it is, so if you want to know more about both (or even one) of these topics then this book is essential. However this is not all you will get from this book.
This book is one of the best books I have ever read in computing (in fact in any field) and is a must for anyone teaching or learning computer science (or writing books). Guttag simplifies and explains well in English, what other books struggle to explain, without drowning you in mathematical concepts. Guttag uses PyLab that is part of mathplotlib library (which is free, easy to install and start using) to help visualise, model and understand the computational algorithms from the later chapters of the book.
I cannot stress enough how Guttag has done wonders with what can be seen as complex and difficult areas. The content is broken down into manageable chunks. His writing is so clear and concise and uses humour and real life examples to explain concepts as wide ranging as recursion, simulation and statistics, in a manner that not too serious, enlightening and often entertaining.
Even if you have been intimidated by these subjects then as long as you have a basic understanding of maths then this book can help you become more confident. The section on how statistical data can both inform and misled you is one of the many examples that you will learn about.