We provide a new approach to issues of order and disorder. We use natural numbers to build an explanatory model which is based on a + b = c. The model helps us to understand the combinatorics of theoretical genetics. A contemporary reformulation of major principles of explanations of Nature provides answers to some of the open questions in this area of research. The book invites readers to an active role in the process of understanding, but it is also well suited as a general introduction to innovative methods relating to the predictability of nature, specifically to basic methods of information processing in biology. The general logical principles presented in the book can be used to derive a wide variety of algorithms, practical and useful in many fields.