To my understanding, the current world is largely uni-polar.The neo-liberal economic ideas have been propagated to promote this unipolarism. I will expect more interesting answers from the fellow researchers.
There is nice book you may refer "The unipolar world: An unbalanced future". It tells how after 1990, the world gradually moved towards unipolarity in term of economic, political, and military.
The reference is: Mowle, T., & Sacko, D. (2007). The unipolar world: An unbalanced future. Springer.