What are the similarities and dissimilarities between the methods adopted by Otto Von Bismarck and Sardar Vallabhbhai Patel?
As regards similarities between Bismarck and Patel, I have no specialized knowledge. Both of them used a 3-stage system for uniting their countries; 1) Invite Union, pointing out the advantages. 2) Take advantage of the fact of human nature that people who will not unite FOR anything will unite AGAINST something - Austria/France, or Britain/Pakistan. 3) By the time only a few states are left outside the Union, the Union will be strong enough to incorporate the rest by force.