I read a German translation of the Portuguese, mainly in the attempt to improve my German, so take my impressions of the book with a grain of salt.
This is a modern fable, trying to capture the feeling of a moral story, with a generous dose of mysticism. We follow an unnamed shepherd, who dreams of a treasure at the foot of the great pyramids of Giza. Despite being happy and comfortable with his nomadic life, he decides to follow this yearning for more, setting out on the journey for this treasure.
The book has a strong message: that each of us has a purpose in life, and that we need to strive to discover it, and not be afraid to pursue our dreams, even in the face of uncertainty. With enough intention, the universe will conspire to realize our dreams. This message is wrapped up in a good amount of Orientalism: the wisdom of the desert, being at one with the universe, hidden symbols in life, etc.
This is a message that was not new at the time of the book's writing, but was not as present as it is now. It's been many decades since the message of following your dreams and your heart has been repeated across various films, novels, and songs, so it feels a bit trite nowadays. Back when this book was published, it was not exactly novel, but it was more of a familiar echo than a repetitive drone.
Disparaging the message for how much we agree with it is unfair. But it does get a bit corny at times, especially with how often the message is repeated within the book itself. Sometimes, more words are spent repeating how important finding your life's purpose, chasing your dreams, looking for the symbols pointing to your personal treasure, etc. rather than advancing the plot.
The presentation of the book is otherwise quite well done. There's a timeless levity to the book. Elements are presented plainly, but with an attention to beauty and wonder, which makes the book a very cozy read. Despite the well-trodden message, the novel does take some surprising twists on the way to its predictable destination.
The novel is a bit more interesting if you read it as a parable about the author's own life. They became a writer after already starting their career, so being able to write this book was, in itself, an achievement in following their own dreams. As much as this message has been repeated to us, it is still one worth paying attention to, and this book presents it in a charming way.