In this chapter, after having been led to differentiate retrospective and prospective temporal judgments, the reader is introduced to the main psychophysical methods for studying the perception of time. This chapter then reveals the limits of Weber’s law applied to time. We also learn that different factors, such as the attention paid to time and the structure of intervals whose duration must be estimated, exert an influence on the perceived duration and the variability of temporal judgments. Different models are then described in order to account for the capacity to process temporal information. And after an overview of the main brain structures involved in timekeeping, the chapter ends with a brief description of the role of the temporal dimension in certain pathologies.