Translation:This book describes the Japanese government in the last century.
I'm not going to try to translate any of those huge blocks of text but the important distinction seems to be
pemerintah: sistem ... mengatur kehidupan sosial, ekonomi, dan politik suatu negara atau bagian-bagiannya;
System of organising society, economics and politics of a country or part of a country.
pemerintahan: proses, cara, perbuatan memerintah The process, method or action of governing.
So I guess the second could be translated as "Governance" rather than "Government"