The book that should be better known???

Oh right - another difficult one Vanessa. There are so many good books out there that should be better known. 
Perhaps we should start with a dictionary? I like dictionaries. I own rather a lot of them. Some of them are in foreign languages, others are "subject specialist". I have a "visual" dictionary - with pictures to show me what the word "means". That one is rather fun actually - and very useful if you are explaining something to a child. 
I know when I worked in school libraries that some of the most popular books were things like "The Cat in the Hat" dictionary and the Richard Scarry dictionaries.
I love my Oxfords - I have the two volume, the "shorter" and the "advanced learner's". The last is precious. It was given to me by the poet, the late Judith Wright.
Then there is poetry. 
Whatever one's religious feelings there are some wonderful passages in the King James' version of the Bible....poetry written by a committee! There is some good advice in that book too. Perhaps we should be taking more notice of it.
Pablo Neruda's "Extravagaria"contains several of his finest poems - in my opinion. I have the bilingual edition. That perhaps? Or perhaps TS Eliot's Collected Poetry?
Or what about going back to the "Ortha Nan Gaidheal" or "Carmina Gadelica" that Alexander Carmichael translated? There are some magnificent passages in that. 
I also like books of quotations. A good book of quotations, perhaps the Oxford one again - or a multi-language one would be even better. They can give me an insight into other minds, other cultures and other ways of life.They can make me think.
And then there is "Markings" or "Vagmarken" in the Swedish - Dag Hammarskjold's book of fragments, thoughts, poetry, haiku and more. It is a book which looks deep into the mind of a man at the top of one of the world's most complex and diverse organisations - the United Nations. It is not a book about the position he held or the politics he had to deal with. It is a book about doubts and fears and concerns, about relationships. God gets mentioned but you don't need to believe in God or be "religious" to read it. It's a book about each and every one of us. It would do some of our current leaders no harm to read it.