It is my duty to remember thankfully, the valuable contribution of my beloved students of Don Bosco Matriculation Higher Secondary School, Pondicherry, India. Without whose help my endeavour would be a failure one.

     Very evidently, Masters Balasubramani. A, Mahendra Varma, Balamurugan. S, Gopinath, Padma Prasad have collected the useful materials. Masters M.Arokianathan, Sylvester Arokiaraj, Ivan Jeffrey, Gnanadevan, T.V.Sampath Raj have helped in typing the manuscript. Master A.Michael, Kasturirangan shared my burden in collecting the relevant pictures.

     Recognition is vital to bring forth the best. The above said contributions are an evident for this. As a token of recognition and appreciation with great pleasure and gratitude I dedicate my works to the students.