In The New Yorker,Nick Paumgarten describes the fascinating process by which the names were arranged for the The National September 11 Memorial in New York:

Arad arranged the requests using index cards. Each pairing set off a chain reaction, the strings of connection growing ever more tangled and frayed. There were two thousand nine hundred and eighty-two names. The deeper he and his staff got into this puzzle, the more complex it became, especially in light of the aesthetic requirements: for example, he didn't want names lining up evenly atop each other, lest there be gutters between them. He had to factor in the number of letters in each name. He had to consider the leading.

Even if you are not a typography nerd, it is a pretty good read.