A system, method and apparatus for maximizing the effectiveness and efficiency of learning, retaining and retrieving knowledge and skills includes a learning engine that includes a novel model of human learning that adaptively determines a memory indicator for each item to be learned for each user during all phases of learning, including a short active phase of learning in which items are actively recalled and a long passive phase of learning in which items are passively forgotten. The memory indicator is determined based on a user's actual memory performance during the short-term active phase of learning and is accurately predicted based on mathematical modeling during the long-term passive phase of learning. The learning model makes use of a target level and an alert level of memory performance for each item of information for each user and the learning engine schedules presentation of items for review or study based on the user's performance with respect to the target and alert levels. The learning engine operates to present to the user items to be learned by the user when a memory indicator value for an item is equal to or below the alert level and stops presenting items to the user when the memory indicator for that item is equal to or greater than the target level for that item.