An approximation method, suitable for an analytical treatment of the K
ramers-Henneberger potential in three dimensions, is presented. The me
thod is applied to various potentials which are currently used in one
and three dimensions with reference to the problem of an electron in a
strong field. This approach is shown to lead to a better understandin
g of the approximations previously adopted to deal with Coulomb and wi
th localized potentials. Moreover, in the case of polynomial potential
s of the double-well form, the method predicts a striking change in th
e dynamics of the electron for suitable values of the physical paramet
ers.