to know of

[Offroad]

Dear friends...

Could you help me to understand the difference between 'know' and 'know of'?

Do you know of any doctor?
Do you know any doctor?

Many thanks

 

[SoothingDave]

Dear friends...

Could you help me to understand the difference between 'know' and 'know of'?

Do you know of any doctor?
Do you know any doctor?

Many thanks

Not a teacher.

"To know" implies a personal experience.

"To know of" means you have information, but not personal experience.

 

[sarat_106]

Not a teacher.

"To know" implies a personal experience.

"To know of" means you have information, but not personal experience.

Yes, to know of is an idiomatic use, meaning: to have information about someone or something.
Q. Who is that person you mentioned just now?
A. We've never met, but I certainly know of him.
The expression ‘not/none that I know of’ is standard spoken phrase to answer in the negative (I do not know). As an example, when you're asked "Is there a planet other than the earth that sustains life?
You can say: "None that I know of." (It means you think it may be possible that there is, but you don't know or heard about it.)