This book summarizes a wide range of recent developments in synthetic methodologies and strategies for the preparation of all possible structurally diverse types of saturated pyrimidine compounds, published in the literature during the last decade (from 2015 to May 2025). This book is divided into two parts based on the type of key strategies used to synthesize these compounds. The Strategy I is divided into five sections, each of which focuses on the synthesis of monocyclic and condensed compounds containing a specific structural type of saturated pyrimidines, including their spiro-fused and bridged derivatives according to Evans' classification, either via cyclization of the appropriate acyclic precursors or by skeletal editing of other heterocycles. In addition, each section presents compounds with biological activity synthesized during this period. The Strategy II includes two sections, which are devoted to the dearomatization of the pyrimidines and the transformation of partially saturated pyrimidine derivatives with retention or increase of their degree of saturation, respectively. It is especially necessary to emphasize that the review also discusses the mechanistic aspects of the synthesis of these interesting compounds.