Research themes in Dielectrics - past and present, similarity and difference [Editorial]

"A rolling stone gathers no moss" is a famous English proverb. It seems to have contrary meanings depending on whether the moss is considered to be a ripe apple or a rotten apple. The first meaning suggests that there is no achievement if we change constantly. Perfection is perpetual work for "the ripe apple." The second meaning suggests that change is compulsory if we seek to carve a niche for ourselves in the new scheme of technology in this rapidly changing world. Innovation abhors stagnation or "the rotten apple." We need both attitudes, and we had better seek a balance between them.