Abstract: Working memory training and whether or not it is effective in yielding transfer to higher cognitive functions such as fluid intelligence has been the recent focus of many controversial discussions. Although we and others have repeatedly observed transfer in various domains and populations, others failed to observe such transfer. We think that in order to understand the features and parameters that promote training success, it is becoming increasingly important to look beyond single studies. I will report the results of a quantitative meta-analysis demonstrating that working memory training can be, indeed, effective. I will also point out that there are several factors moderating the extent of transfer, such as pre-existing individual differences and motivation. Furthermore, I will discuss potential underlying mechanisms of training and transfer and argue that researchers need to develop innovative approaches to move the cognitive training literature beyond the simple question of whether or not training is effective, but rather focus on determining for whom cognitive training is most useful and why. I will conclude with the notion that despite the growing evidence, we are still at the opening bell in investigations of cognitive training and its benefits, and I will outline some of the current outstanding questions, such as the longevity of training, its application in educational settings, and its real-life consequences.