Mendeley is a free reference management and academic social networking tool that allows users to organize research papers and citations, collaborate with other researchers, and extract metadata from papers to build a research catalog. It consists of Mendeley Desktop software to organize papers and citations and Mendeley Web, which contains a database of over 250 million papers from 2 million researchers and enables collaboration and sharing. Mendeley aims to make research more transparent and social by addressing problems with existing reference tools and databases.