In 2002 The Dr. Bernard Heller Foundation awarded a grant to the library for the full restoration of one of its most treasured manuscripts, the Prato Haggadah (Ms. 9478).

The Prato Haggadah (Spain, ca. 1300) is an unfinished illuminated manuscript of 85 leaves, written on fine calf parchment. It measures 8 ¼ x 5 7/8 inches (21 x 14.9 cm). Most of the quires comprise 8 leaves; there are 7 leaves in the ninth quire and 6 leaves in the tenth quire. Folios 1–53 are written in a square Sephardic script and folios 54–68 are written in a square Italo-Ashkenazic script, using a different ink.

The illumination of thirty pages is virtually complete. Fifty-eight are unfinished, with preparatory drawings and possibly some gesso and color, fifty have text only and the remaining pages are blank. Many of the pages have illuminated initial word panels, comparable to illuminated initials in Christian or secular manuscripts. Throughout, illustrations accompany the text, such as the depiction of the four sons, and illustrations of matza and maror (bitter herbs). Preparatory drawings depicting the story of Noah and the flood appear at the end of the manuscript. Margins are replete with fanciful drawings of hybrid creatures, imaginary birds, drolleries and climbing vines.

The codex is especially fascinating because it demonstrates the making of a manuscript in the Middle Ages, enabling us to view its illumination after the text was written: the preparatory drawings, the laying down of gesso in order to cushion the gold leaf, the application of gold and silver leaf, and ultimately the application of pigments. The skill of the artist is of a very high order, both in the preparatory drawings and in the completed pages, whose brilliant colors look as fresh today as when they were applied.