What are the primary and secondary themes in Stuart Little?

A primary theme of Stuart Little is the importance of optimism to the human (and mouse) spirit. Stuart has an enormous deck stacked against him as a tiny mouse in New York City and in trying to adapt to life in a human home, yet he is ever resourceful, cheerful, and optimistic. Although only a mouse, he exemplifies the triumph of the spirit over adversity. He becomes a symbol, in fact, of the undaunted human spirit. For example, the fact that he has to struggle with the simplest tasks doesn't make him bitter. Instead, he is determined to succeed, and his outsized spirit and loving attitude seems to more than balance his small size.

A secondary theme is the struggle of the outsider to adapt. No matter how hard he tries and how much love and acceptance he receives, Stuart can never truly overcome being a mouse in human society. He will never be human. He realizes how vulnerable he is in a big city like New York and recognizes that he will have to get into his car and travel north if he wants to be who he truly is. He knows, as he embarks on his journey, that, although an outsider, he is “headed in the right direction.”

One of the primary themes presented in this book is accepting diversity.  Stuart Little is a mouse, in the book born into a human family who accepts him and makes adjustments for his smallness. There is an issue of the differences Stuart has compared to his human family.  These differences can become an obstable since George is a little disappointed by his brother who can't really be the playmate that he was expecting.  So George has to accept his brother for who he is and this is done through Stuart's remarkable personality.

Stuart is very courageous, he is not afraid to charge into difficult situations, like getting his mother's ring out of the drain.  He races a boat in Central Park, crawls inside the piano to fix the keys for his brother and decides to look for Margalo, setting out to find her without any thought for his own safety. 

Stuart can be viewed from the Little's perspective as a special child, and it is often said that special children born into a family may look different, act different, but are always a special gift.  Stuart symbolizes this because he is so extraordinary that it is easy to overlook the differences that he has with his human family.

What are the three main themes in the novel Stuart Little?

Probably the most important theme in Stuart Little deals with acceptance of diversity. Stuart and his family learn how to adapt to each other's differences and come to each other's aid when it is needed in order to cope with a particular situation.

To get to the washbasin, Stuart had to climb a tiny rope ladder which his father had fixed for him...For such a small fellow, turning the water on was quite a problem. He had discussed it with his father one day..."Maybe I could pound the faucet with something and turn it on that way," he said. So Stuart's father provided him with a very small, light hammer made of wood; and Stuart found that by...letting it come down with a crash against the handle of the faucet, he could start a thin stream of water flowing...

Closely related, a second theme has to do with the virtues of adaptability and flexibility. Stuart's size presented challenges at times but could also be used to advantage.

When the bus came into view, all the men waved their canes and brief cases at the driver, and Stuart waved his spyglass. Then, knowing that the step of the bus would be too high for him, Stuart seized hold of the cuff of a gentleman's pants and was swung aboard without any trouble or inconvenience whatever.

The third major theme highlights the joys of undertaking adventures. Stuart discovers a whole world of beauty and new experiences when he leaves home to search for his beloved friend Margalo.

In the loveliest town of all,...Stuart stopped to get a drink of sarsaparilla....It seemed to him a place he would gladly spend the rest of his life in,... if it weren't for the fact that something deep inside him made him want to find Margalo.