Mihaly Makai 
Group Theory Applied to Boundary Value Problems with Applications to Reactor Physics [PDF ebook] 

In order to fully apprehend the conceptual aspects of the world, we need to look at the practical applications of those concepts, as the book provides a popular application of the wondrously captivating mathematical concept of group theory. For most of us laymen, mathematics is conceived primarily as arithmetic, something to do with quantities. However, the real beauty of mathematics emerges when it is about qualities and relations. Maths helps us to understand bewildering complexities of life and the universe, from basic particles to infinite galaxies. It is this fundamental scientific understanding that transforms into the applications that eventually yield constructive change in the world. The wide overview of this book gives generously, both to those who seek the purity of understanding, and those who are attracted to hands-on applications.