Cells, Microcells, and Picocells --Book Structure -- Review of GTD/UTD and Physical Optics Techniques -- GTD/UTD Approach -- Direct Field -- Reflected Field -- Edge-Diffracted Field -- Transmitted Field -- Multiple Effects -- Validation of GTD/UTD Models -- Application of GTD/UTD on SemiDeterministic Models -- Physical Optics -- Application of Physical Optics in Semi-Deterministic Propagation Models: Multiple Knife-Edge Diffraction -- Application of Physical Optics in Deterministic Propagation Models: Scattering Field -- Vector Transformations -- Vector Transformations Between Rectangular and Spherical Coordinate Systems -- Vector Transformations Between Rectangular Coordinate Systems -- Vector Transformations Between Spherical Coordinate Systems -- Fresnel Transition Function -- Ray-Tracing Techniques -- Geometrical and Morphological Models -- Geometric Description -- Morphological Models -- Faceted Models -- Rationale for Ray-Tracing: The Shadowing Problem -- Ray Propagation Models -- The Shooting and Bouncing Rays Method -- Image Method -- Ray-Tracing Acceleration Techniques -- The Binary Space Partitioning Algorithm -- The Space Volumetric Partitioning Algorithm -- The Angular Z-Buffer Algorithm -- Rigorous Determination of Diffraction Points -- Rigorous Ray-Facet Intersection Algorithms -- Ray Intersection Algorithms With Arbitrary 3D Facets -- Ray Intersection Algorithms With Particular 3D Facets -- Normal Vector of an Arbitrary Facet -- Backface Culling.