The central nervous system (CNS) completes its maturation with characteristics that are peculiar to it: a general process of development regulated according to an established genetic prescription that proceeds throughout gestation, and even thereafter, plus a topographical feature in which each anatomic sector executes its portion of that general developmental pattern with its own rhythm and timing, changing in morphology from one week to the next. We thus see that to the structural complexity inherent in the genetic program itself is added on the accompanying feature of the CNS's asymmetrical and characteristically topographical maturation. Over the course of time - and always aiming at establishing time limits for case diagnosis - neuropathologists have tried to delineate strict developmental parameters for the CNS. The relationship between specific malformations and embryonic or fetal age was established. The association of CNS diseases with precise gestational ages was first documented in the early descriptions of the hypoxiaischemia lesion in preterm neonates, even though the details of the etiology were not elucidated until a much later time. Thus, the tryptic of lesion-timetopography looms up as a present-day challenge that, though hardly novel, has reemerged in these recent years as an important element in case diagnosis, while at the same time becoming modified upon incorporation of the revolutionary discoveries within the field of molecular biology. This article briefly summarizes certain precursors of these phenomena and cites the opinions and contributions of the relevant authors within the subject. Moreover, as an inevitable consequence of the complexity of neural epigenetic development, this treatment also underscores the difficulties associated with the interpretation of pathological images. Finally, and as an innovative notion, the term "molecular timing" is proposed. Although in its essence the concept is found dispersed throughout the publications dealing with molecular discoveries, it is nevertheless novel because of its terminology and the conceptual integration that its fundamental meaning achieves.