The collection was the working library of James Simson (1740-1770), 2nd Chandos Professor of medicine at St Andrews, and was bequeathed to the Library in 1770. It includes many items previously owned by his father Thomas Simson (1696-1764), the 1st Chandos Professor. There are over 200 volumes of medical books of the 16th to 18th centuries. The collection includes a coloured copy of Dioscorides, De medicinali materia, Frankfurt, 1549 and a copy of Vesalius', De humani corporis fabrica libri septem, Venice, 1568, which was used as a teaching aid by the Simsons. It has many additional illustrations, cut from the 1725 edition and stuck in.
The Simson collection is fully catalogued and available via the online catalogue here. Classmarks for books in this collection have the prefix Sim.