Catherine C. Marshall, doing research on the future of user interface design, has studied the phenomenon of user annotation of texts. She discovered that in several university departments, students would scour the piles of textbooks at used book dealers for consistently annotated copies. The students had a good appreciation for their predecessors' distillation of knowledge. In recent years, the marginalia left behind by university students as they engage with library textbooks has also been a topic of interest to sociologists looking to understand the experience of being a university student.