Upgrading ideas about the concept of Soft Computing

This short note is devoted to introduce the discussion carried out along this special issue on the concept of Soft Computing by key researchers in the field. We shall stress some aspects of the conception and origins of Soft Computing, supported by the scientific relevance of its participants. The contributors will show their own view about a single question, What is Soft Computing?, covering answers from a general historical approach to the role of some specific tools within their expertise. This discussion represents an extremely interesting view about the concept of Soft Computing, its meaning, its related techniques and its relationship with close fields.