Deathworld

Books 4-7 in the series were co-written with various Russian authors and were published in Russian. According to the Harrison Web site, there are no plans to publish these books in English. The extent of Harrison's involvement in these projects is unknown.
Wikipedia

Titles (10)

# Title Author(s) Year Type
1 Deathworld Harry Harrison 1960
2 Deathworld 2 Harry Harrison 1964
3 Deathworld 3 Harry Harrison 1968
4 Возвращение в Мир Смерти Harry Harrison & Ант Скаландис 1998
45 Мир Смерти на пути богов Harry Harrison & Ант Скаландис 1998
5 Мир смерти против флибустьеров Harry Harrison & Ант Скаландис 1998
6 Мир Смерти и твари из преисподней Harry Harrison & Ант Скаландис 1999
7 Мир смерти. Недруги по разуму Михаил Ахманов & Harry Harrison 2001
The Deathworld Trilogy Harry Harrison 1974 Omnibus
Возвращение в Мир Смерти Harry Harrison & Ант Скаландис 1998 Omnibus