Topic models provide a simple way to analyze large volumes of unlabeled text. A "topic" consists of a cluster of words that frequently occur together. Using contextual clues, topic models can connect words with similar meanings and distinguish between uses of words with multiple meanings. For a general introduction to topic modeling, see for example Probabilistic Topic Models by Steyvers and Griffiths (2007).
Voyant Tools is a web-based text reading and analysis environment. It is a scholarly project that is designed to facilitate reading and interpretive practices for digital humanities students and scholars as well as for the general public. You can find out more about Voyant or read the documentation on...
N. Tran, S. Zerr, K. Bischoff, C. Niederée, and R. Krestel. Proceedings of the Exploration, Navigation and Retrieval of Information in Cultural HeritageENRICH 2013 Workshop at SIGIR 2013, (2013)