Let's face it, The Lord of the Rings is a big book full of lots of things, and those who have read it will have their own (and usually) passionate feelings about it. I certainly cannot do it justice within the limited scope of this document; however, I am going to try to share some thoughts about it.
It seems to me that The Lord of the Rings boils down to three things. Firstly, it is about generational change: the passing of people and of situations. Secondly, it is about letting go: giving up attachments to people, places and power. Finally, it is about how we are to act in a dangerous world.
Tolkien chose to do this within the genre that he and C.S. Lewis called Heroic Romance. Working within this genre, Tolkien created a fictional world that never existed, and one that is both very familiar and very alien. The task before him was to take the reader from the familiar and slowly introduce them to the unfamiliar world of men and elves, and of war and magic. This is what Book One of The Fellowship of the Ring is about. Let's consider how he combines his themes and his task.
As was told in The Hobbit, Bilbo Baggins made a remarkable journey into the Wilderness with thirteen dwarfs and the wizard Gandalf. As a result of this adventure, Bilbo came into the possession of a one-fourteenth share of a vast treasure. He also found a magic ring. That was when he was fifty. Bilbo is now eleventy-one, and he celebrates this birthday by holding a big party. He has also decided to depart from the Shire, leaving his nephew Frodo as the owner of Bag End and of the magic ring. Here we have both generational change and a letting go.
Seventeen years later, it becomes clear that the Shire is no longer a safe place. Dark forces are searching for Frodo's ring, which is revealed to be the One Ring that controls all the other Rings of Power. Frodo, it is decided, must leave the Shire and journey to the haven of Rivendell. Frodo is reluctant to let go of the Shire; he has not had his fill of it.
The journey will be a dangerous one. At first Frodo is accompanied by Sam Gamgee and Pippin Took, and they are soon joined by another hobbit, Merry Brandybuck. They encounter many dangers before reaching the village of Bree, where they are joined by a mysterious stranger: a man called Aragorn (and nicknamed Strider). These five plunge into the true Wilderness as they head for Rivendell. They face discomfort and danger together and, by looking after one another in times of peril, become true friends.
It is not only in such friendship that we find clues about how we are to act in the world. There is a deeper attitudinal component to the tale. The words "hope" and "pity" are sprinkled throughout the text: "...hope came to him in the darkness..." "It was pity that stayed his hand." And these words are set in opposition to "despair" and "malice" and "revenge". It is through hope and pity that Gandalf seeks to help a frightened Frodo begin his journey. "Don't despair!" Strider tells a distraught Sam.
Tolkien takes us from the very familiar world of the Shire - with its mills and pubs, its gardens and farms - and across the landscape of Middle Earth; and as the travellers inch their way forward, the world becomes more wondrous and more perilous. By degrees we are introduced to the strange, the beautiful and the deadly. First, a brief encounter with a rider dressed in black provides some horror. This is followed by a meeting with a band of elves, who give comfort to the hobbits. Leaving the Shire, they meet with forces that are far older and more powerful than they can imagine: Old Man Willow and Tom Bombadil are personifications of the wild forces of nature; the barrow-wight is a locus of the malign power in the world.
Tolkien also tells us of the history that underlies the story. The second chapter of the book is almost totally devoted to Gandalf relating to Frodo the history of the One Ring. It is a story that goes back to events several millennia in the past. Later, on the Barrow Downs, we get glimpses of the history of a war that was fought centuries ago. And later still, Aragorn tells the hobbits a tale of Beren and Luthien, who lived some seven or eight thousand years earlier. It is a deep history. And so Tolkien's story is given breadth and depth by geography and history.
Tolkien's achievement is quite remarkable. By the end of Book One, the reader is steeped in a world that is not real and only exists in their own mind; a world that can never be visited but can be experienced most vividly - this, perhaps, is one reason why The Lord of the Rings is a book that enjoys a widespread and enduring popularity - and it sets the stage for the ever-widening action of the following five books.