The review on research on the development of metacognitive knowledge shows that declarative and procedural metacognitive knowledge components seem to follow different developmental trajectories. There is clear evidence that declarative metacognitive knowledge increases substantially from the early elementary school period on, with gains still observed in adolescence and young adulthood. On the other hand, one of the major outcomes of developmental studies on procedural metacognition concerns the lack of clear-cut developmental trends in children's and adolescents' monitoring skills. By contrast, the available evidence on the development of self-regulation skills demonstrates that there are clear increases from middle childhood to adolescence. The links between metamemory, memory behavior (strategies), and memory performance have also been frequently explored during the past three decades. Overall, the findings point to nontrivial quantitative associations between metamemory and memory. Several multivariate studies have shown that metamemory about strategies is an extremely important type of metacognition.