Intelligent spaceship vs imprisoned monster - What is the name of the story?

I am trying to find the name of a scifi story I read probably 40 years ago.

I don't remember all the elements, but there is a spaceship that itself communicates with a young man on Earth (or other planet). The ship is almost the main character. I believe the ship chose the man for some reason. The ship may take the man to other planets, and at various points in the story protects the man while on a planet with a personal shield.

What I remember is just a very, very sophisticated spaceship with a chosen human partner from a planet, with the mission of solving the problem of an imprisoned beast.

There is a very dangerous creature imprisoned in a very distant system by a possibly extinct civilization which made the spaceship. The prison may be at the center of the galaxy. There may be three suns in the prison system.

I don't remember the plot but I remember I really liked the story and would like to read it again. Thanks for any help.

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