One article by this man divided the world into the world (*) island, the offshore islands, and the outlying islands, and posited that whoever controlled the Heartland at the center of the World Island would control the world.
With Michael Sadler, this thinker advocated university extension in one work, and another work by this thinker was followed up with an article in which he stated that the USSR had captured a key position in his theoretical framework.  He published a history of the Rhine and eight lectures on India, as well as an introduction to civics entitled The Modern British State. One article by this man divided the world into the world (*) island, the offshore islands, and the outlying islands, and posited that whoever controlled the Heartland at the center of the World Island would control the world. For 10 points, name this geographer who expanded geopolitical analysis worldwide in his "The Geographical Pivot of History".
With Michael Sadler, this thinker advocated university extension in one work, and another work by this thinker was followed up with an article in which he stated that the USSR had captured a key position in his theoretical framework.  
Halford John {Mackinder}