The story of a mechanical creature who wishes to become human is an old one, appearing in many forms over the centuries. In this superb story, a robot, named Andrew by the children who adore it, begins to exhibit human characteristics, due to the unpredictability of its' positronic memory circuits. Slowly, through a series of step-wise modifications, Andrew is altered so that his functions become more human. Throughout the tale, Andrew exhibits many of the characteristics of being human, although his human society is currently exhibiting a backlash against robots doing anything to appear as anything other than robots.
This is also a tale about human politics, emotions and insecurities. Some of the prejudices exhibited against robots are strikingly similar to those humans have against other humans not of the appropriate type. Asimov and Silverberg are masters at describing the consequences of technology and in this book, they are at their best. I have always considered Asimov's robot stories to be the best of all his science fiction works. They deal with limits placed on technology, through the hard-wired laws of robotics to the social restrictions placed on robots so that they do not appear too human. And yet, he also presses the envelope, in that he has humans becoming intimate with robots, even to the point of suggested sexual contact.
I consider this to be one of the two best science fiction books that Isaac Asimov wrote, with the other being Nightfall. It is an old tale, but told with emotional entanglements, such as having Andrew being treated not as a monster but as a member of a human family as he pursues his quest to be declared legally human.