Yegor gaidar's Death of the Empire is highly recommended. A very, very good academic book written by Russians, which is rich in all kinds of materials and deeply describes the social state before the disintegration of the Soviet Union.

If you don't need academic knowledge, it's good to have a book "Soviet Union", which is published in China with many pictures and simple content. I think these two books are objective, and many ideologies published in other countries are too heavy, even if they are read, they are useless.