Biography.com: Campanella, Tommaso: Very short outline of this scholar's life.
Catalog of the Scientific Community: Campanella, Tommaso: Basic biographical facts, compiled by the Galileo Project.
Catholic Encyclopedia: Tommaso Campanella: In-depth article on the strange career of the Italian anti-Aristotelian Dominican writer.
Columbia Encyclopedia: Campanella, Tommaso: Brief biographical entry.
Encyclopædia Britannica: Campanella, Tommaso: Biographical entry from the 1911 edition. With bibliography. Some scanner errors.
Readings in Modern Philosophy: Tommaso Campanella: Links to various resources on this thinker, and an online excerpt from Weber's History of Philosophy.
The Philosophy of Tommaso Campanella: Article from the Radical Academy, concisely reviewing Campanella's philosophical, religious and political teachings.
Wikipedia: Tommaso Campanella: Biography of the Renaissance thinker, hyperlinked to related topics.