The book gathers review papers in emergent engineering applications and new horizons in nonlinear dynamics, and originates from DYCAELS 2023, the IV Conference on Dynamics, Control and Applications to Applied Engineering and Life Science, which was held in Ponta Grossa, Brazil, on November 6-11, 2023. The contributions cover diverse topics such as linear and nonlinear control, vibro-impact systems, energy harvesting, robotics, bioengineering, flexible structures, non-ideal excitation, aeroelastic instabilities, new materials, synchronization, stochastic dynamics, multistable systems, nonstationary dynamics and different time scales, wave propagation, chaotic dynamics and mechanisms and machine science.