The present book describes calculation of Sadhana index, its modeling ability and uses in nanotechnology. The important aspect of the book is the introduction of the orthogonal cut method for estimation of the Sadhana index in that we have considered three types of edges namely vertical, horizontal and oblige. The corresponding orthogonal cut is then utilized for estimation of Sadhana index. This methodology is used world wide for estimation of graph theoretical descriptors related to nano structures.