29a. Book by Michele Hauf first published in 2004 with a paperback edition in 2006, the first book in the Changeling series: ????????
4d. Another name for the White Poplar: A?E?E
37d. --- Butenandt, 1939 winner of the Nobel Prize for Chemistry: ????F
21a. Heroe of Homer's epic work: O?Y?S?U?
19d. A chessman other than a pawn ??E??