I've had this book for a while and always go back to it. I've recommended it to many friends as I am always glad that it was recommended to me. Well worth the read, guaranteed!
Henri Nouwen examines his life after a near death accident in which he encounters the Living God.
Facing the possibililty of dying he is able to let go and let God's unconditional love come to him and accept himself as God sees him.
His recovery from the accident brings about many changes in his attitude towards his family, friends, acquaintances and yes even his enemies. The experience brought resolve and forgiveness for his sins and the sins of others.
To come back to the living and take his daily cross was very difficult, since he had already prepared himself for the next life with Christ. To return to the former routine seemed impossible at that time but before long he had gone back to his former ways and was constantly trying to keep the peace that he had found during his illness.
Another book that touches on going to the mountain top and coming back would be "Hind's Feet on High Places" an allegory by Hannah Hurnard.