Mathematics was first used by the ancient people for counting their belongings. Counting further developed into addition (+), subtraction (-), multiplication (*) and division (/). But so far, no attention has been given to the determined act of arrangements in mathematics in our day to day life. This book therefore, aims at opening the whole world to a completely new field of mathematics --Determined Arrangements. One important game of nature played by all of us is the sex game. During this act we enjoy, but after sex, what happens inside the woman's womb, no one really knows, yet we expect the result as we like. Biologists try to explain the events inside a woman's womb in terms of the theory of the probability, which generates more doubts than answers. Rely on the theory of probability in explaining the happenings inside a mother's womb would mean all off-springs could not be born in the average frame time of 9 months. A woman's womb however, is just like a toy manufacturing factory, with different assembly lines, giving the output of each toy at pre-determined time intervals. The book further explains the applications of this theory in mathematical manner, for example, in answering questions like how egg selects matured sperm, how egg and sperm further form into reconstituted gametes, how chromosomes cross-over in meiosis 2, how both reconstituted gametes further develop into the Tree of Life, how the resulting off-spring comes as a boy or girl but not as a hermaphrodite, how twins come as boys, girls, boy and girl but not hermaphrodites, how four pairs of nucleotides are arranged on Another very important application of this work is in determined secured communication system in combating piracy in Information and Communications Technology.