This 1895 map of New York City was created by socialist activist Walter Vrooman, who hoped that by showing the "concrete socialism" of every street, park, school, public building, and public dock in red (and allowing private enterprises to recede into the white background), he might persuade readers that the rest of the map should be socialist as well.
From the Norman B. Leventhal Map Center/Boston Public Library
E-mail John de Cuevas the revealed phrase. Solvers will be listed below in the order received. Check back May 15th for the hints and solution!
You can find all 35 puzzles published in Harvard Magazine between 1986 and 1998 at John de Cuevas's website‚ www.puzzlecrypt.com‚ under Harvard Puzzles. You will also find additional puzzles and contact information there and can subscribe to his mailing list.