CREATE TABLE table_2901 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "U.S. viewers  ( millions ) " TEXT)

Who wrote the episode seen by 10.64 million people in the US?
SELECT "Written by" FROM table_2901 WHERE "U.S. viewers (millions)" = '10.64'
SELECT "Written by" FROM "table_2901" WHERE "U.S. viewers (millions)" = '10.64'