British Library MS Royal 17.B.XX contains a single sermon by Donne, his famous 1622 Gunpowder Plot sermon. The manuscript is of considerable importance since it is the only surviving witness containing evidence of Donne's hand. Though written out by a scribe, Donne frequently interfered with the text, supplying corrections and emendations. More information about the manuscript is accesible when you navigate to the individual sermon, and from John Donne's 1622 Gunpowder Plot Sermon: A Parallel Text Edition, ed. Jeanne Shami (Pittsburgh PA: 1996).