Preheat oven to 350 degrees F (175 degrees C). Line cookie sheets with aluminum foil or baking parchment.

In a large saucepan, melt the butter over medium heat. Add peanut butter and sugar and stir until melted. Remove from heat.

Transfer to large mixing bowl and stir in bran cereal. Stir in eggs and vanilla and mix well. Fold in raisins and oatmeal and stir until well blended.

Sift together flour and baking soda and add to mixture. Mix thoroughly.

Drop dough by tablespoonfuls onto cookie sheets. Dip a fork into water and press to flatten dough to 1/2 inch thickness.

Bake for 15 minutes, or until cookies are lightly colored. Reverse sheet once during baking time. Let stand on wire racks to cool.