The 77-year-old filmed more than 40 documentaries, including the 1968 'Fidel', based on a week-long trip around Cuba with the now ill Castro. He died on Wednesday.
Among other topics addressed by Landau in his films were the 1970-73 government of Chilean president Salvador Allende and the 1994 Zapatista uprising in Mexico.
The 1979 documentary, 'Paul Jacobs and the Nuclear Gang', co-directed by Landau and Jack Willis, won an Emmy and the George Polk Award for investigative reporting.
The documentary explored health effects of US atomic bomb testing in Nevada in the 1950s. He also wrote 14 books.