I shall first discuss the variations of magic numbers and shell structure in exotic nuclei by using effective single‐particle energies. An origin of these variations is shown to be the spin‐isospin dependent part of the nucleon‐nucleon interaction in nuclei. Such variations can be referred to as the shell evolution. As an outcome of this shell evolution in neutron‐rich exotic nuclei, magic numbers such asN=8, 20,etc.can disappear, whileN=6, 16,etc.arise. The shell gap is changed as a consequence of the shell evolution, and a good example is shown for30Na. An interesting case regarding shapes of exotic nuclei is presented for excitation energies andB(E2) values of32,34Mg exotic nuclei. It is suggested that various anomalous properties of exotic nuclei can be studied with the paradigm of shell evolution. In the second part, recent results of shell‐model studies will be presented for some Sn and Te nuclei. The anomalousB(E2) value of136Te can be explained within the shell model description which has described the spherical‐to‐deformed phase transition in Ba isotopes. © 2003 American Institute of Physics