Mate in Two by the Badger

Clues are in standard grid order of the square of the first letter of their solutions, from a8 in the NW corner to h1 in the SE corner.  They contain an extra letter in the definition which must be ignored.  Punctuation may mislead. Solutions which begin in an empty square are entered normally, across or down.  Solutions which begin in a square occupied by a chess piece (including pawns) have their first letter placed in that square and the remaining letters, in any order, placed in all squares to which that piece could legally move, including captures.  All 22 pieces on the board are clued (four are abbreviations). Squares with WHITE or BLACK letters contain pieces of the respective colour; otherwise, they contain no piece. In the resulting position it appears either player can immediately deliver mate in two.  Solvers must determine who is next to move (determinable from the grid fill) and write under the grid the mate in two.  The extra letters spell out a quotation and the author’s initials.  Submissions must include the 64 letters but need not show the chess pieces