Read in Portuguese.
These Asimov's books has earned a special place in the sci-fi genre and it's well deserved. It's a Masterpiece!
But it is not for all kind of readers. It's "Like it or leave it!" kind of book.
I don't recommend it for those people who like to read something quickly and full of action. To fully enjoy Foundation you need to read this book without today's perspective, I mean, it's been written in the 1950's, and inspired so many writers that the ideas about future in these books aren't fresh and new anymore. And you need to read all three because the Foundation series gets better with each succeeding book.
I think Asimov is a writer's writer. You can see in his books inspirations that may have impacted others people's works.
I recommend it only to people who really love reading science fiction books.
P.S.: I do apologise in advance if my English leads to any misunderstanding.