This is the 882nd most frequent Portuguese word.
bom
"Bom" means "good" in English.
In this sentence, 'bom' serves as a general quality descriptor, expressing a positive condition or feeling.
É bom saber que você está bem.
It's good to know that you are well.
The word 'bom' is again an adjective, qualifying the type of work performed on the project as being of good standard.
Ele fez um bom trabalho no projeto.
He did a good job on the project.
Here, 'bom' is used as an adjective describing the quality of the book.