Preheat oven to 400° F.
Combine raisins and water in saucepan; boil 5 minutes.
Blend sugar, cornstarch, cinnamon and salt in a bowl. Add to raisins and cook, stirring until clear. Remove from heat. Stir in lemon juice and butter. Cool slightly.
Roll out half of pastry into a circle large enough to fit bottom and sides of 9-inch pie pan. Place in pie pan. Turn slightly cooled raisin filling into pastry-lined pie pan. Roll remaining pastry, and cover pie with a solid circle, or lattice strips. Trim and crimp edges.
If using solid top crust, cut slits into it.
Bake 25 minutes, or until crust is brown and filling is bubbly.
Cool pie completely before slicing.