Eugene Garfield can certainly be considered one of the giants of information science. Garfield’s life, as shared in his obituary by Subbiah Arunachala, is intertwined with the history of the development of machine indexing and use of the computer’s capability to enable access to scientific papers by exploring the basic tool of the citation. This pioneer in information studies created Current Contents, Science Citation Index and his company ISI. He did groundwork that led to the Medical Subject Headings (MeSH). He made great leaps by recognizing the value of the citation itself and developing a way to make them more accessible to researchers.
His website: http://www.garfield.library.upenn.edu/
His essays: http://garfield.library.upenn.edu/category.html
including Was the Science Citation Index concept inevitable? (mentions the value of the citation). Link at http://www.garfield.library.upenn.edu/geneticscitationindex.html