Advanced Mechanical Models of DNA Elasticity includes coverage on 17 different DNA models and the role of elasticity in biological functions with extensive references. The novel advanced helicoidal model described reflects the direct connection between the molecule helix structure and its specific properties, including nonlinear features and transitions. It provides an introduction to the state of the field of DNA mechanics, known and widely used models with their short analysis, as well as coverage on experimental methods and data, the influence of electrical, magnetic, ionic conditions on the persistence length, and dynamics with viscosity influence. It then addresses the need to understand the nature of the non-linear overstretching transition of DNA under force and why DNA has a negative twist-stretch coupling.