  The radical-pair mechanism was introduced in the 1960's to explain
anomalously large EPR and NMR signals in chemical reactions of organic
molecules. It has evolved to the cornerstone of spin chemistry, the study of
the effect electron and nuclear spins have on chemical reactions, with the
avian magnetic compass mechanism and the photosynthetic reaction center
dynamics being prominent biophysical manifestations of such effects. In recent
years the radical-pair mechanism was shown to be an ideal biological system
where the conceptual tools of quantum information science can be fruitfully
applied. We will here review recent work making the case that the radical-pair
mechanism is indeed a major driving force of the emerging field of quantum
biology.
