The book was published, awkwardly, right after the breakup of the USSR, but since it was in print, and the authors took great pain to gather all the information possible to the newly opened up USSR without having to be restricted by Intourist, the publishing went ahead. And also - this is also long before LP became the mainstream guidebook it is today. The audience, you can sense, was a completely different crowd and so was the book content.
You will have great fun travelling with this, and discover the changes and the future that they saw for the communist empire.