When Clay Felker and Milton Glaser founded New York magazine in 1968, they intended it to serve as a native consumer’s guide to NYC. Glaser described how Felker’s influence caused him to look at the city with a fresh eye in Duke University’s alumni magazine
One of the great problems in life, and certainly in art, is that you become immune to everything you become familiar with. The great thing about Clay was he was unfamiliar with so many things about the city. What Clay did for me was to make me look at what I was already familiar with again. And I think that’s actually a very good sort of general definition of what happens in the creation of art, which is the examination of the familiar. Most often what familiarity means is that you simply stop looking at something. I discovered that when I was sitting at a table deciding to draw my mother… I had no idea what she looked like. Clay led us all into a willingness to look at things that we had stopped looking at years ago, those of us who had grown up here.
The same approach applied to The Underground Gourmet, which began as a friendly competition between Glaser and Jerome Snyder, each attempting to out-do the other in his knowledge of cheap eats in NYC. The Underground Gourmet eventually landed in the pages of New York magazine; its first appearance there featured famous knish-maker Yonah Schimmel.
The Underground Gourmet emphasized value, in addition to obscurity and quality. For The Underground Gourmet, a relatively good luncheonette meal that was dirt cheap was just as noteworthy as today’s perfectly delicious replica of Colombian street food that is nonetheless overpriced.

The above sketch of Mi Tierra was probably used in the magazine, and I believe that’s Jerome Snyder in the foreground. The entry from The Underground Gourmet book paints this picture for the intrepid diner:
The difficulty and discomfort that one may encounter before getting around to eating the rather good food at the Mi Tierra may be enough to discourage all but the most dedicated value seekers. The restaurant is a visual disaster… The wallpaper is a peeling simulated brick. Overhanging the entrance is an enormous blue-painted air conditioner which originally must have been used for cooling a battleship… Your order is taken promptly enough, but the length of time until the dish itself materializes before you is both inexplicable and interminable and, if you are very hungry, unendurable. The authors have averaged a 50-minute wait even when there was only one other customer in the restaurant. The reward turns out to be authentically prepared, tasty, quite well-arranged Mexican food at a reasonable price… Mi Tierra, in addition to its good food, provides an interesting experience. The critical question for the individual diner to decide for himself is whether his discomfort threshold is high enough to endure some of the environmental difficulties.
Also from the book, a special section on cuchifritos breaks it down for the uninitiated:

Easy: Papa Rellena: “Orange colored dumpling like mashed potato mound, gently spiced with ground pork filling – a Latin cousin to the knish.”

Difficult: Oreja: “This mild flavored, grisly object is a pig’s ear. It is on the fatty side and cooked in a thin tomato sauce.”
The Underground Gourmet book is illustrated with custom logos featuring some of Glaser’s early typefaces B&H (still at 127 Second Avenue!) is done in Baby Fat; La Foccaceria (the East Village Sicilian landmark that survived until 2006) sports a relative of Baby Teeth.

