2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/202227Examples are presented of applications of the Lemaître - Tolman model to problems of astrophysics and gravitation theory. They are: 1. Inferring the spatial distribution of matter by interpretation of observations; 2. Interaction of inhomogeneities in matter distribution with the CMB radiation; 3. Evolution of voids; 4. Singularities; 5. Influence of electromagnetic field on gravitational collapse. This review is meant to demonstrate that the theory is already well-prepared to meet the challenges posed by an inhomogeneous Universe.13 pages, LaTeX, Contribution to the proceedings of the 49th Yamada conference on black holes and high-energy astrophysics. To be published by Universal Academy Press, Tokyo; email: akr@camk.edu.plGeneral Relativity and Quantum Cosmologytext