We interpret the difference between aware and unaware forms of memory in terms of Polanyi's distinction between tool and object. Aware memory, such as recognition and recall, occurs when memory serves as an object of attention. Unaware memory occurs when memory serves as a tool to accomplish a present task. Both memory-as-tool and memory-as-object can rely on memory for specific prior experiences. Memory used as a tool is a pervasive form of unconscious influence. We present experiments in which memory used as a tool enhances perception, lowers the subjective experience of background noise, increases the fame of nonfamous names, and lowers estimates of the difficulty of anagrams. To escape the pervasive effects of unconscious memory, one must consciously remember the past experience, understand its influence in the present task, and possess a good theory to serve as an alternative basis for behavior. These three criteria may seldom be met.