Well, the Strugatsky brothers were writers of so called soft (social) SF (in contrast with Роза и Червь which is a brilliant example of hard SF). To the Strugatsky's books you mentioned, I'd like to add The Kid and Inhabited Island. They are absolutely must-read too.
And if we talk about soft SF, there is yet another talented SF writer. Eugeny Lukin. In my opinion, he is much more Russian in spirit than Soviet Strugatsky. I do not want to offend anyone, the Strugatsky brothers are good SF writers too. But if one wants to read
Russian SF, one definitely should read Lukin's books.
Евгений Лукин
в Википедии,
на сайте fantlab.ru и
на сайте flibusta.net.
(I'm pretty sure I've made some grammatical mistakes in this post. Corrections are welcome.

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