The book "Conserved Quantity" by Betascript Publishing offers a comprehensive introduction to the concept of conserved quantities in dynamic systems. It covers the mathematical foundations and the significance of conserved quantities for the qualitative analysis of systems. The work relies on articles from Wikipedia and other free sources to present a wide range of information. Conserved quantities are functions of the dependent variables that remain constant, thus providing valuable insights into the dynamics of systems. The book also highlights the fact that not all systems possess conserved quantities and that their existence is not necessarily linked to the linearity of a system. This makes the study of conserved quantities particularly relevant for understanding nonlinear systems.