diff --git a/fontconfig/fontconfig.h b/fontconfig/fontconfig.h
index bae92fe..1f0bd9c 100644
--- a/fontconfig/fontconfig.h
+++ b/fontconfig/fontconfig.h
@@ -101,6 +101,7 @@ typedef int		FcBool;
 #define FC_WEIGHT_EXTRALIGHT	    40
 #define FC_WEIGHT_ULTRALIGHT	    FC_WEIGHT_EXTRALIGHT
 #define FC_WEIGHT_LIGHT		    50
+#define FC_WEIGHT_BOOK		    75
 #define FC_WEIGHT_REGULAR	    80
 #define FC_WEIGHT_NORMAL	    FC_WEIGHT_REGULAR
 #define FC_WEIGHT_MEDIUM	    100