The authors continue the book series entitled Contemporary Fundamental Physics. Edited by Professor Doctor V. V. Dvoeglazov from Universidad de Zacatecas, Mexico, this thematic issue Relativity, Gravitation, Cosmology: Beyond Foundations contains chapters related to contemporary problems of modern physics. This book includes an Editorial Introduction and eleven chapters, commentary, and several reprints. This book may also be considered as the continuation of past publications found in the authors own series concerning relativity. This issue includes contributions from M. Land, V. V. Varlamov, E. Kapuscik, I. A. Vernigora and Yu. G. Rudoy, E. M. Ovsiyuk, V. V. Kisel and V. M. Redkov, O. V. Veko, S. I. Kruglov, B. G. Sidharth, A. Gutierrez-Rodriguez, M. A. Hernandez-Ruiz and A. Gonzalez-Sanchez, and V. V. Dvoeglazov. Older research concerns quantum field theory and gravitation theories. Recent research has been presented at the XI Workshop (2015) and the X and XI Schools (2014 and 2016) of the Gravitation Division of the Sociedad Mexicana de Fisica. The book will be useful to researchers, professors, and students of physics and mathematics.

We continue the Book Series ''Contemporary Fundamental Physics". The thematic issue "Einstein and Others: Unification" contains articles related to the problem of the unification of interactions and to other fundamental problems of the modern physics. The book includes an Editorial Introduction, and nine articles. This book may be considered as continuation of the books "Einstein and Poincare: The Physical Vacuum" and "Einstein and Hilbert: Dark Matter", published by us a few years ago. The authors are: S Capozziello, M De Laurentis, L Fabbri and S Vignolo, D J Cirilo Lombardo, S I Kruglov, V V Varlamov and M V Beloborodova, C Pierre, W A Rodrigues Jr and E Capelas de Oliveira, A Krasulin, and V V Dvoeglazov.

This book presents interesting mathematical questions of relativity theory and relations to modern astrophysics, as well as various conceptual foundations. Topics discussed include the generalised Lorentz transformations and the velocity transformation; fundamental physics; non-Newtonian gravity effect; dark matter and dark energy concepts; pseudo-complex variables and antisymmetric tensor fields. This book will be useful for academic professors, professional researchers in physics and mathematics, postgraduate students and all remaining people interested in theoretical physics and astrophysics.