I would recommend Fundamental Chess Openings by Paul van der Sterren. It gives a good overview of openings and would be better suited for someone with his rating. Modern Chess Openings is ok but I would not recommend it in his case --- MCO is more of a reference for the vast number of lines within the openings.
Looking for a good openings book with illustrations

I would recommend Fundamental Chess Openings by Paul van der Sterren. It gives a good overview of openings and would be better suited for someone with his rating. Modern Chess Openings is ok but I would not recommend it in his case --- MCO is more of a reference for the vast number of lines within the openings."
I just checked on the Internet, and I found an online version of FCO. It seems really interesting and easier to understand than MCO, as you said !
Thank you very much; I'm gonna buy this one. I think he will like it

You're welcome. What I like about it is that it gives a good overview and explains the ideas behind the openings in a way that is accessible to non-master level players.

Another good one for understanding openings rather than memorizing is Reuben Fine's Ideas Behind the Chess Openings.

Good Chess Openings Books For Beginners and Beyond...
https://www.chess.com/blog/RussBell/good-chess-openings-books-for-beginners-and-beyond

Hello everyone,
My friend would love to have a chess book that focuses on openings for Christmas, but he told me that he likes books with some chessboard illustrations to understand better and memorize the moves.
His rating is about 1000, and he wants to improve, maybe join a chess club soon, so I don't know what could be better for him.
I heard about the book called "Modern Chess Openings," what do you think about it? Do you have any other references to recommend? (We are french, so if you have books written in french to recommend, I take it too !)
Thank you