Complex sentence: Santiago has written many article on Puerto Rico's military history, and over 600 articles covering most other facets of Puerto Rican and Latino life as well as scores of biographies of prominent Puerto Rican figures.
Split into simpler sentences: Santiago has written many article on Puerto Rico's military history. In addition he has also written over 600 articles covering most other facets of Puerto Rican and Latino life as well as scores of biographies of prominent Puerto Rican figures.