I am the author of two books on global issues, who listens to at least a hundred serious non-fiction books a year.
I and Thou is a classic as it deserves to be. Like many classics, it is an unusual book. It is about connecting directly with the God in each being we encounter. It is about how we might share in deep and genuine connections with our fellow humans and how we might find God within the world of human relations.
At its best, the book succeeds in laying out a new paradigm of spirituality, one that is neither focused on some externalized God, nor the God within, nor the God of unity. For Buber, God can best be sought in each if our relations, in the way we relate from moment to moment.
It is a beautiful book, imbued with Buber's own unique language. The only problem is that Buber's language is not always easy to understand. Part of the reason for this may lie in the translation; philosophical works in German are notoriously difficult to comprehend. There is also a long tradition of philosophical obscurantism amongst German philosophers of which Buber is sadly a part. But it is a language and phrasing that marches to its own inner rhythms, and it is as unique as its message. Altogether, it is a beautiful book to which one might do yoga or tai-chi or take a walk in the woods.
Martin Buber is an early-to-mid twentieth century German-Jewish philosopher. He wrote like Heidegger at his best before Heidegger. And he was one of a small handful of Jewish immigrants to Israel, before it was Israel, who advocated for a one-state for Jews and Palestinians to share. This was before the one-state solution was being advocated as an alternative to the two-state solution, which came after the solution was ethnic cleansing. Whereas Heidegger was a Nazi, Buber was a genuine humanitarian, and it shows in his work. Buber was far ahead of his time; hence, it should not surprise us that he wrote such a timeless classic.
The reader stays out of the way, not interfering with the text, so that it might speak for itself. Altogether, the result is a beautiful experience that can be returned to repeatedly.
There is no other ancient writing like this. I was there in the story. I was moved by God's love for his people. The clarity of the text is remarkable. I have read many many ancient religious texts but none of them hold a candle to the Tanakh. God's relationship with mankind is clear.