New York City's rapid transit system went beyond what we know it as today. Although the most well-known unbuilt line has been the 2nd Avenue Subway (part of which is now being completed after delays dating back to 1929), there have been many other plans announced that would have stretched the system out to and beyond the city limits in all five boroughs. All of the subway system plans, realized or unrealized, strongly influenced the development of New York City as a whole. For a significant part of the 20th Century, the system was planned to expand ahead of the development of residential and commercial areas. Developers looked to purchase land in the service areas of the new lines. The Routes Not Taken looks at how some developers tried to use the growth of the transit system to make their properties more valuable. In addition, The Routes Not Taken looks at some of the people who both positively and negatively affected the growth of the transit system. Some of them are still well-known (Mayors Fiorello H. La Guardia and James J. Walker and Robert Moses), others have been forgotten with time (John H. Delaney, who ran the transit system for decades, and planners like Daniel L. Turner). The Routes Not Taken is intended to provide readers with an understanding of how the transit system could have grown beyond its current limits and the conditions and actions that kept it from expanding further and how it actually contracted over the years.