| His annotations to an incunable edition of Old Frisian law reveal his interest in Anglo-Saxon canon law. |
| There are over 6,000 volumes in the collection which also includes about 30 incunable. |
| This edition of the Book of Psalms was the first Hebrew book printed in Naples, a centre of Hebrew printing in the incunable period. |
| The work was printed in 1493 by Anton Koberger, and includes 1809 woodcuts from 645 blocks, making it the most richly illustrated incunable. |
| He seems to have had little direct contact with the British Museum, except that in November 1943 he presented one French incunable to the museum. |
| Foxcroft annotated a copy of the larger catalogue for each additional incunable placed in the collection. |
