From this position King's Gambit Quaade Variation,
[fen "rnbqkbnr/ppp2p1p/3p4/6p1/4Pp2/2N2N2/PPPP2PP/R1BQKB1R w KQkq - 0 5"]
If white plays 1. d4 then 1... g4 2. Bxf4 gxf3 3. Qxf3 is forced. If white tries to prevent that then 1. g3 g4 2. Nh4 Be7 is bad for white which is sadly the book's only suggestion. What should white do about this?