It is well known that solid carbons can be found in various guises with different forms of bulk phases (graphites, diamonds and carbynes) as well as more molecular forms (fullerenes,nanotubes and graphenes) resulting from recent discoveries. The cause of this rich polymorphism is analyzed in the first part of this book (chapters 1-5) with the propensity of carbon atoms for forming different types of homopolar chemical bonds associated with variable coordination numbers. Prec