The Twelve Days Of Christmas, by Hilary Knight. New York: Macmillan Publishing Company. 34 pp. $8.95.

In this interpretation of the the familiar Christmas folk song, the ''true love'' is Benjamin, a roly-poly bear, who bestows gift after gift upon his beloved, Bedelia. We first see Benjamin on the road to Bedelia's house, pulling a partridge in a pear tree on a little wagon, and then huffing and gamboling along as his bounty increases. Bedelia, shown in her distant house, is busily engaged in domestic pursuits to find uses for Benjamin's gifts. She makes ice cream from the pails of milk, converts pears into jam, and sends the calling birds flying to deliver her holiday invitations.

Other images show Hilary Knight's gift for illustration. The most charming picture is the Christmas fair at the end, where all the gifts play a role, and Bedelia shows Benjamin that she can think of one good use for two of the accumulation of gold rings.