As requested; here is the recipe for the sourdough starter. It's pretty easy. This is verbatim from the book, however, I usually just use all purpose flour and tap water and it seems to work as well.
1) In a large bowl combine 1 ½ cups bread flour, ½ cup rye flour, ½ package active dry yeast and 2 cups bottled spring water. Cover the bowl with a cloth and let sit at room temperature for 3 days. The mixture will bubble, smell slightly sour, darken slightly and collect a watery liquid on top.
2) On the fourth day, stir in ½ cup flour and ½ cup water; repeat on the 5th day. Use starter in bread dough or refrigerate in a sealed container.
3) For longer storage, once a week remove 1 cup starter; replace with ½ cup flour and ½ cup water.