The main interest of this brief book lies in the search of a theory of gravity that is consistent from the quantum point of view. If this is the physics that the reader is interested in, this book will be useful as an entry point, especially for graduate students and researchers from other fields looking for an introduction before delving into the vast literature. (Valerio Faraoni, Mathematical Reviews, April, 2022) All the models presented in the book are analyzed in detail, showing their strengths and weaknesses, in particular the causal coherence of the theory (analyzing the Goedel-like solutions) and the possible consistence with quantum theory (renormalizability). This book gives a good guidance for those scientists who want to face the field of alternative theories of gravity. (Daniele Montanino, zbMATH 1470.83004, 2021)