Many great thinkers have reported benefiting considerably from the book of Ecclesiastes (or ‘Koheleth,’ as it’s known in Hebrew). The word ‘Koheleth’ directly translates as the assembler of the people and true to its title, the book states, for these people, the author’s conclusions of his long and fully-lived life.
Ecclesiastes is both an incredibly easy book to synthesize (its leading refrain—that all is ‘hevel’ or vapor/meaningless—is repeated throughout) and a great challenge to explain (it’s nihilism is found essentially nowhere else in the Bible).
Personally, I’ve not benefited much from the wisdom literature of the Scriptures, but I think that is because it is so challenging to understand. Yet, on my most recent read-through of Ecclesiastes it made sense like never before. I hope, perhaps, I am learning what Solomon learned without the painful end that he experienced.