Many studies have been conducted on the topics of tools, computers, and technology designed to promote student learning. However, researchers have rarely raised the critical issue of the lack of consensus on conceptualizing "cognitive tools" or the possible challenges associated with previous definitions. By examining the limitations on research on cognitive tools and proposing new perspectives for future research with cognitive tools, the goal of this article is to answer the following questions: (1) What is a cognitive tool?; (2) What are the (un)answered problems with cognitive tools?; and (3) What questions should be addressed for future research and practice with cognitive tools? In exploring the first question, this article critically analyzes historical views on computers in education and examines the background of cognitive tools along with selected examples used in science education. Then, accounts of the second question raise problems with investigating cognitive tools outside of the social context. Finally, the third question concerns the need to shift the focus of cognitive tool research "from" the interactions between cognitive tools and individual learners, and the technological capacities for supporting such interactions, "to" learners' knowledge construction in authentic, sociocultural contexts and the tools-in-use in those learning contexts. (Contains 3 tables, 1 figure, and 1 footnote.)