Very good analysis of friendship and interesting reflections.

The Discovery of Heaven from a simple story: the friendship of two young men (Max and Onno), yet with tastes and opinions rather different, who met "by chance" (I emphasize the quotes, you can understand by reading the book). Despite their differences, their friendship is based on one thing they understand is to say they can predict the response to the other. Then joined the Ada group, a young cellist whose fate is pathetic.
We quickly takes a liking to the strong friendship of Max and Onno, we understand the real meaning of it with the novel by Harry Mulisch. Small reflections interspersed in the narrative (which correspond to those of the characters) are very interesting though sometimes original.
However the meaning given to the story - that is to say the search tables of the Act (which only appears at the end of the novel), ordered by the angels - is to my taste a bit confused unlike the rest of the novel.
The Discovery of Heaven is still an excellent book that I recommend so.