In a large bowl, cream together the butter, sugars, eggs, and vanilla until smooth. Combine the flour, baking soda, cinnamon, and salt in a separate bowl. Stir into the sugar mixture. Stir in the oats, raisins and walnuts. Refrigerate the dough for 1 hour. Drop by rounded teaspoonfuls onto ungreased cookie sheets. Flatten slightly with the bottom of a glass.
Bake 10 minutes. Don't overbake them! Let them cool for 2 minutes on the cookie sheets before moving them to wire racks to cool completely. Store these in an airtight container.