Peter Gunning was born in Kent and matriculated at Clare College, Cambridge in 1629, graduating in 1633. Gunning remained at Clare until he was ejected by parliamentary commissioners in 1644 due to the royalist sympathies manifested in his preaching. He then moved to be with the royal court in Oxford, where he stayed as chaplain of New College until the royalist surrender. For ten years he served as a tutor and chaplain in the households of various royalist nobles, before commencing preaching to a congregation with royalist sympathies at the chapel of Exeter House on the Strand. Services using the Book of Common Prayer were tolerated discreetly in the main, although parliamentarian troops did interrupt Gunning's Christmas Day communion in 1657. After the Restoration his career took off: he resumed his fellowship, became Lady Margaret Professor of Divinity, Master of Corpus Christi College, and then, in 1661, Master of St John's. He also gained positions in the Church, most notably prebendary of Canterbury Cathedral. Due to his reputation as one of the foremost churchmen of his day he took part in the Savoy Conference in the hope of reconciling episcopalian and presbyterian parties in the Church. Eventually Gunning resigned his post as Master of St John's to become Bishop of Chichester in 1670, and then of Ely in 1675.
Gunning gave half his library to St John's, and the other half to his executor, William Saywell, for life, before returning them to the use of the College. There are several thousand books in the College's collections which bear his provenance, and although many of these concern theology and canon law, most other subjects are covered as well, notably politics, history, classics, poetry and the sciences. The sheer scale of his bequest ensures that there are numerous volumes of interest, including the following:
Gunning's books almost all bear a book label detailing his bequest. Translated it reads:
From the gift of the Very Reverend Father in Christ, Lord Peter Gunning, firstly Bishop of Chichester, then of Ely, a most consumately pious and learned man, once a long-celebrated Professor of Holy Theology in the University of Cambridge, afterwards Master of this College of St John the Evangelist, to which he bequeathed by his will three hundred pounds on top of the same amount which he had already given, together with his whole most substantial library. In the year 1684.
Many also bear his arms stamped on the front cover, with the College badge on the rear cover, usually in blind but occasionally in gold.