Bridges' Dynamics covers the historical review of research and introductory mathematical concepts related to the structural dynamics of bridges. The e-book explains the theory behind engineering aspects such as 1) dynamic loadings 2) mathematical concepts (calculus elements of variations the d' Alembert principle Lagrange's equation the Hamilton principle the equations of Heilig and the Δand H functions) 3) moving loads 4) bridge support mechanics (one two and three span beams) 5) Static systems under dynamic loading 6) aero-elasticity 7) space problems (2D and 3D) and 8) absorb systems (equations governing the behavior of the bridge-absorber system). The e-book is a useful introductory textbook for civil engineers interested in the theory of bridge structures.