Very large floating structures (VLFS) are used for storage facilities, bridges, ferry piers, docks, breakwaters, rescue bases, entertainment, military purposes, petroleum industry needs, even airports and habitation etc. These structures can be constructed and exploited fast, easily relocated, expanded, or removed. VLFS are reliable, cost-effective, and environmentally friendly. The main idea in proposed concepts is to build a very large mat-like structure whose thickness is small compared to its horizontal length parameters. This book subject is hydroelastic analysis of a VLFS that is the study of the motion of a floating elastic plate and its response to surface water waves. Various problems of VLFS-water waves interaction are treated. The plate deflection and free-surface elevation are studied as well as the reflection and transmission of water waves. Different methods of applied mathematics, mechanics and hydrodynamics are employed, such as water wave propagation, diffraction, Kirchhoff thin plates theories and Green''s theorem. Conclusions and recommendations are given. This work can also be used for analysis of water waves interaction with ice fields.