Abstract: Smart or adaptronic structures are structures with an ability to respond in a pre-defined useful and efficient manner to changing environmental conditions, including any changes in their own condition. Since they are designed and used by human beings, the overall design philosophy should encompass the role of the human user also. Another viewpoint is that they are nothing but a synonym for good engineering. They should possess characteristics close to, and, if possible, exceeding those found in bio-materials. Adaptability is their main feature. In the so-called passively smart materials, this comes about as a standby property. But in actively smart materials or structures there has to be a field-tunability of properties. This, in turn, requires nonlinear response. The vicinity of a ferroic phase transition at the temperature of application provides the nonlinearity feature. But there are also several other ways of achieving nonlinear response. Use of soft matter is one such way. Exploitation of mesoscopic structure is another. Mimicking biological structures also entails the incorporation of a “brain” or control centre. Advances in artificial intelligence and neural networks continue to provide the impetus to the field of smart structures. An overview of the subject will be given.