Prepare Basic Pie Crust. Line a 9-inch pie plate with half of the pastry.
Place the cranberries and water in a saucepan. Cover and cook for 6 to 8 minutes, until the skins pop. Add the tapioca, sugar, salt and pears. Mix well and cool. Turn into the prepared pie plate and dot with the butter.
Cut the remaining pastry into strips and make a lattice top for the pie; or cover with solid pastry. Trim, turn under and flute the edge. Prick the crust to allow for escape of steam if a solid crust is used.
Bake the pie for 10 minutes. Reduce the heat to 350°F and cook for 30 minutes longer, until brown. Cool.