In the early nineties, at the initiative of Sinha and financial support of Shah and Liski (from their respective Research Project Funds), the authors - inspired by their similar research interests - started collaborative research at various institutions mostly in pairs and triplets. It took more time and efforts on the part of MandaI to visit the others at regular intervals and keep track of their common as well as diverse research areas and merge his own. From this collaborative work, the concept of this monograph took a preliminary shape only last year and serious efforts were started to...