Write Who You Know: In A Beautiful Friendship, the Harringtons have a meeting at a restaurant called "The Red Letter", owned by a person by the name of Eric Flint. The fictional Flint is said to hail from the world of New Chicago, described as "a dumping ground for radical anarchists, socialists, and - especially - every member of the Levelers’ Association the government could round up after Old Earth’s Final War". The Real Life Flint, an occasional co-author with Weber in this and the 1632 series, is a self-admitted socialist, and currently lives near Chicago. Also qualifies as a Shout Out.