identify three past stages in marketing model building and implementation, review the current status, and provide some intriguing thoughts on how the model-building process may evolve in response to ongoing and anticipated developments in the marketing environment. It is interesting to note that time-series techniques are not mentioned in their review of the past, receive considerable attention in their assessment of the current situation (mainly in the context of the insights these techniques can provide on marketing's long-run effectiveness), and are again absent in their speculations about the future. In this paper, we complement and extend on Leeflang and Wittink's discussion in three ways. First, we discuss why, in the past, time-series techniques received little attention from marketing model builders and users. Second, we show how each of the identified obstacles has recently been attenuated, and review more extensively the recent contributions of time-series applications to marketing science. Finally, we elaborate on some expected future developments in marketing research, and discuss opportunities and challenges to applied timeseries modelers.