This is the editio princeps of the Stowe Psalter preserved in the British Library manuscript, Stowe MS 2. This mid-eleventh-century manuscript used to belong to Sir Henry Spelman, and the editor of this edition, John Spelman, is his son. Later the manuscript came into possession of Richard Temple-Nugent-Brydges-Chandos-Grenville, 1st Duke of Buckingham and Chandos and was kept in Stowe House, which is why it is called the Stowe Psalter now.
The main text in this manuscript is a Gallican Psalter (in Latin), to which Old English interlinear glosses are added above each line. In the edition, Spelman follows the original and prints not only the Latin text but also the Old English glosses, while (understandably enough) omitting all the decorations.
My copy has a bookplate of Reverend J. W. Kenworthy, who seems to have been a vicar of Braintree, Essex.
Its latest edition is Andrew C. Kimmens, ed., The Stowe Psalter (Toronto: University of Toronto Press, 1979).