If you're interested in the reasons behind and the results of the Russian Revolution of 1917, that changed the course of history for both Russia and affiliated countries forever, then you'll have to choose your sources carefully.
The most definitive and comprehensive modern book about the Russian Revolution is Orland Figes' A People's Tragedy: The Russian Revolution 1891-1924. The narrative is easily digestible, the explanations clear. However, this book is huge at around 800 pages. While its size is testament to the amount of quality information contained within, sometimes we need answers to be presented in a more succinct manner.
My suggestion is to definitely acquire a copy of A People's Tragedy, but use it as a supplement to a textbook that addresses this period in Russian history more broadly. Then, if you want more information about individuals, events, or or other aspects of the Russian Revolution, turn to Figes' well-researched and readable account. And really, deeper reading can be valuable, because textbook-like introductions to the Russian Revolution can gloss over some of the more intricate details or ignore them completely. It is, after all, important to note that circumstances were so dire in the early 1920s in Russia, Ukraine, and elsewhere, that people were resorting to cannibalism to survive. You won't get information like that from textbooks, but you will get a proper explanation and examples in A People's Tragedy.