Who is Justice James Marshall Harlan from Gideon's Trumpet and what is their importance?

Harlan is the Justice who writes another of the assenting opinions in Gideon's case. Harlan says the previous standard, Betts vs. Brady, deserves a "respectful burial." Harlan says that Betts had served a purpose by indicating that defendants had the right to counsel past the capital cases, but that it had provided for "special circumstances." Harlan says the "special circumstances" rule itself has had a "troubled journey" and that the rule has apparently come to the point of no longer being a reality.