Why does Frodo leave on the boat?
It is one of the central conceits of Tolkien’s larger legendarium that these events exist in a time of transition. The elves, who had long been in a state of decline, were leaving Middle Earth, taking ships back to a paradise across the sea. The Ring-bearers (Bilbo, Frodo, and Sam) are permitted to take that journey themselves. As , ends, Frodo and Bilbo take that last journey, while Sam will depart later, long after the events of the book.,Ultimately, you should remember that Frodo returns from his quest to destroy the ring severely traumatized. We see a physical manifestation of his trauma in his recurrent illness but even more severe than his physical suffering are the emotional and psychological scars he bears. Tolkien himself attests to the weight of Frodo’s suffering in one of his letters, writing (on the subject of Frodo’s failure as a hero):,These are strong sentiments, which are well reflected in the melancholy tone that becomes particularly strong within the last part of the book. One can see this sense of melancholy present when the Hobbits return to the Shire, only to find that the home they had spent so long trying to safeguard and protect had in the meantime been transformed into something unrecognizable. As Tolkien writes:,Of course, at this point, the Hobbits participate in a rebellion, restoring the Shire to much of its earlier beauty and tranquility. However, while this physical damage can be repaired, Frodo’s alienation and emotional trauma is much more difficult to counteract. While Sam is able to reintegrate, making a life for himself in the Shire, marrying and building a family, Frodo cannot. As he tells Sam:,Thus, Tolkien himself answers your question in that same letter cited earlier (letter # 246) to Eileen Elgar, from September 1963. Frodo, damaged and traumatized, departs from Middle Earth first and foremost in search of solace and healing. In the professor’s own words: