  We introduce the new class of submanifolds of co-Banach type in tame
Fr\'echet manifolds and construct tame Fr\'echet submanifolds as inverse images
of regular values of certain tame maps. Our method furnishes an easy way to
construct tame Fr\'echet manifolds. The results presented are key ingredients
in the construction of affine Kac-Moody symmetric spaces; they have also
important applications in the study of isoparametric submanifolds in tame
Fr\'echet spaces.
