The present invention makes legal research more efficient by selecting clusters in response to the behavior of a user (e.g., a legal professional such as a paralegal, lawyer, or judge). The clusters, which are formed prior to the user accessing a legal document (and thus, providing user behavior to a system), are identified to the based upon a set of metadata associated with the legal document. At least two clusters are identified and a signal associated therewith is transmitted to the user. Each cluster is associated with a unique legal topic. Further, each cluster may comprise primary and/or secondary authority.