This monograph presents a concise discussion of the dynamics of mechanical randomizers (coin tossing, die throwing and roulette). The authors derive the equations of motion, also describing collisions and body contacts. It is shown and emphasized that, from the dynamical point of view, outcomes are predictable, i.e. if an experienced player can reproduce initial conditions with a small finite uncertainty, there is a good chance that the desired final state will be obtained. Finally, readers learn why mechanical randomizers can approximate random processes and benefit from a discussion of the nature of randomness in mechanical systems. In summary, the book not only provides a general analysis of random effects in mechanical (engineering) systems, but addresses deep questions concerning the nature of randomness, and gives potentially useful tips for gamblers and the gaming industry.