Clinical observations and experimental studies in humans and laboratory animals have demonstrated that healing and repair of pulpal exposures by caries, trauma, or iatrogenic causes are possible with a variety of wound treatment methods. Yet clinical trials have shown that predictable long-term pulp tissue preservation may be an elusive goal and has led to doubts about pulp capping and pulpotomy as valid clinical procedures. Nevertheless substantial knowledge has accumulated over the years on the mechanisms and the treatment factors that are important to promote/support continued vital pulp functions. This article highlights some key contributions to our current knowledge base, which have come to light during the more than 50 years since a pioneering experimental study by Zander and Glass was published in the Triple O journal.