What mysteries are left unsolved at the end of Chapter One? Why do you think the auhor has left these questions unanswered?

At the end of Chapter One, we do not know what happened to Mr. Murry, what Mrs. Whatsit did with the stolen sheets, or what the meaning or importance of the "tesseract" is. From the text, we can infer that the three things have something in common, and that the "tesseract" has something to do with Mr. Murry's disappearance. L'Engle uses the first chapter to introduce some of the novel's main characters, to provide background information, and to foreshadow coming events.