Helvetica is a widely used sans-serif typeface developed in 1957 by Swiss typeface designer Max Miedinger with Eduard Hoffmann. Quoted from Wikipedia.

Those in the creative industry, knows very well about Helvetica as one of the widely used font or typeface for graphic design.  Helvetica is also commonly used as the signage typeface of the New York City subway system, used so often that it has became the official typeface of MTA (Metropolitan Transportation Authority). Which prompted Gary Hustwits to make a documentary on how Helvetica took over the subway? To answer the question, Paul Shaw has created a book titled Helvetica and the New York City Subway System: The Truer (Maybe) Story, an illustrated book with over 300 original photos.  In this book, Paul Shaw explores how the subway’s signage has evolved over the years and takes you to understand the chronology of the New York City subway system.