An understanding of the microscale structure and composition of sedimentary rocks is of undiminished importance in diverse fields (e.g., microscale chemical analysis cannot proceed without petrography), yet the curriculum is no longer offering undergraduates the opportunity to develop sufficient expertise. In an effort to bolster the exposure of undergraduates to sedimentary petrology, the Tutorial Petrographic Image Atlas was created. The basic components of the tutorial are petrographic images that are viewed in a static mode (no rotation, no animation, no timed observation). Text boxes relating to identification of components within the image are attached to specific mapped regions of the image. Both the mapped regions and the text are invisible until the student points and clicks on an active region of the image. In essence, the student must 'ask', "What is that?" Information ranges from simple one word identifications to lengthy paragraphs explaining the finer points of why something is what it is. This is a highly interactive digital product that attempts to recreate certain elements of the laboratory petrographic experience including: a sense of exploration; high-quality petrographic images; a visual field dominated by the image; multiple examples of features viewed in diverse contexts; rich content relating to the identification and significance of features; active, inquiry-based learning. Unlike real-time laboratory experiences with the petrographic microscope, the digital tutorial can be used at any time and place that a computer is available, does not require the presence of a microscope or samples or an expert, can be viewed repeatedly, has the technical content integrated with the image, gives the student undivided "attention" (unlike the TA, it doesn't wander to the other side of the lab), and rarely gives answers unless "asked."