How many Soviet republics were there?

There are many works dedicated to the period of the 1920s and 1930s. I can recall two off the top of my head. One is "Stalin. Economic Revolution," but I don't remember the author's name, and the other is Zhukov's monograph "A Different Stalin." They provide figures from archival sources, not just pulled out of thin air. Also, put yourself in Lenin's and Stalin's shoes. The country is in ruins, and enemies are all around. What should they do? They could, of course, surrender to the mercy of the West. Or they could create a strong state. There was no other way.