I collect old car advertising and noticed on a double truck ad for a 1968 VW Bus the headline when laid flat reads-" New Impr oved Box "- I assume this is to remain readable in the middle of a magazine with a huge page count(I bet publishers would love this problem in today's market)What is the gap in the word improved referred to as? I am not a graphics professional so forgive my ignorance
The two pages treated as one layout is called a Double Page Spread. The space between the letters is called Kerning and the part of the double page spread that gets obscured due to the binding is called the Gutter.
The designer of your example increased the kerning between the r and the o to make it more readable across the gutter of the spread.