Reading and understanding somebody else code

It is important for a developer to understand what somebody else code does. It is important for code review. If it is unclear for somebody else of what the code does, then the question can be asked of the developer of what that specific section of the code does. If it is unclear to another developer what that specific code does, than there may be a bug with that code, or implementation can be done differently and more understandable by others. Why code reviews by others is important? It will minimize chances of an error to slip through into production environment. Errors may still slip through to a production environment, even so the code had been reviewed by others, however the chances of an error will be minimized by doing so.