[1] His father, Jose Prados-Herrero, moved the family to San Juan, Puerto Rico, where John graduated from high school.

(1981)[11] Prados continued to design wargames for the rest of his life; the final one, Monty's D-Day, was published the year before his death.

Of the more than twenty wargames created after university, ten were nominated for "Robbies", and three of those were winners: Khe Sahn, 1968 (2002), Fortress Berlin (2004), and Beyond Waterloo (2012).

[13] As reported in the Washington Post, Prados's purpose in designing wargames was not to breed militarism, but to reveal "the difficulty of conducting war" as well as its "horrendous costs.

In 2000 Ellen Pinzur moved from Boston to Silver Spring, Maryland to live with Prados; they remained a couple until his death[14] from cancer[1][2] on November 29, 2022, at age 71.

[15] Combined Fleet Decoded was named by New York Military Affairs Symposium as the recipient of The Arthur Goodzeit Book Award in 1995.