What is the difference between "I know" and "I know of"? I learned "I know" means I have met or talked to someone. On the other hand, "I know of" means I know, even though I have never met or talked. Is it OK? So, what does "I know about" mean? I know Shohei Ohtani, I know of Shohei Ohtani or I know about Shohei Ohtani. Which is correct?