There are two titles for Swedish translations. The older translation is known as Härskarringen. This translation is often called Sagan om Ringen, but that is technically the title of just FR. TT and RK are called Sagan om de Två Tornen and Sagan om Konungens Återkomst, respectively. Tolkien disliked this translation. It was superseded in 2005 by Ringarnas Herre.
For the first few editions of this Swedish translation, the name of the trilogy, Härskarringen, did not appear on either the covers or the title pages. In the earliest editions it is not mentioned at all, but it is mentioned on the dustjackets in later editions, both on the inside front flap and on the back, and in the recap chapters preceding TT and RK. It also appears as the title on the cover of the one-volume editions.
"Härskarringen" (Swedish G), purchased on-line from Annika Hornemark, Hurva, Sweden on Bokbösen in 2024 (paperback)
Tolkien, J.R.R. Sagan om ringen. Translated by Åke Ohlmarks. Gebers, 1967.
———. Sagan om de två tornen. Translated by Åke Ohlmarks. Gebers, 1967.
———. Sagan om konungens återkomst. Translated by Åke Ohlmarks. Gebers, 1967.
Tolkien, J.R.R. Ringens värld: Dokument rörande sagorna om Härskarringen. Translated by Åke Ohlmarks. Gebers, 1972.
When LOTR was initially translated into Swedish in 1959-1961, the Appendices were not translated. A note in that first edition mentioned that they would be translated in the future. They were not published until this edition in 1972 and the volume was titled Ringens värld.
"Härskarringen" (Swedish C), purchased on-line from Antikvariat Sacher, Malmö, Sweden on ABEBooks in 2021 (hardback)
Tolkien, J.R.R. Sagan om ringen. Translated by Åke Ohlmarks. Awe/Gebers, 1985. ISBN: 91-20-05915-9
———. Sagan om de två tornen. Translated by Åke Ohlmarks. Awe/Gebers, 1978. ISBN: 91-20-05916-7
———. Sagan om konungens återkomst. Translated by Åke Ohlmarks. Awe/Gebers, 1985. ISBN: 91-20-05917-5
Tolkien, J.R.R. Ringens värld. Translated by Åke Ohlmarks. Vol. En Samlingsvolym. AWE/Gebers, 1987. ISBN: 91-20-06365-2
From this edition forward, the Ringens värld volume included not just the Appendices to LOTR, but also three short works from Tolkien: "The Adventures of Tom Bombadil", "Tree and Leaf", and "The Homecoming of Beorhtnoth".
These six volumes are often referred to as the "Jubilee Edition".
"Härskarringen" (Swedish H), purchased on-line from SITT OCH SKRIV AB, Vellinge, on Bokbösen in 2024 (hardback)
Tolkien, J.R.R. Sagan om ringen. Translated by Åke Ohlmarks. AWE/Gebers, 1989. ISBN: 91-20-07738-6
———. Sagan om de två tornen. Translated by Åke Ohlmarks. AWE/Gebers, 1989. ISBN: 91-20-07739-4
———. Sagan om konungens återkomst. Translated by Åke Ohlmarks. AWE/Gebers, 1989. ISBN: 91-20-07740-8
Tolkien, J.R.R. Ringens värld: Dokument rörande sagorna om Härskarringen. Translated by Åke Ohlmarks. AWE/Gebers, 1989. ISBN: 91-20-07741-6
Silmarillion (Swedish [S] C), purchased on-line from SITT OCH SKRIV AB, Vellinge, on Bokbösen in 2024 (hardback)
Tolkien, J.R.R. Silmarillion. Edited by Christopher Tolkien. Translated by Roland Adlerberth. AWE/Gebers, 1989. ISBN: 91-20-07743-2
Sagor från Midgård (Swedish [UT]), purchased on-line from SITT OCH SKRIV AB, Vellinge, on Bokbösen in 2024 (hardback)
Tolkien, J.R.R. Sagor från Midgård. Edited by Christopher Tolkien. Translated by Roland Adlerberth. AWE/Gebers, 1989. ISBN: 91-20-07742-4
This is Unfinished Tales.
Härskarringen (Swedish I), purchased on-line from Ars Mats Sacher, Malmö, on Bokbösen in 2024 (hardback)