This book deals with the death of well, Ivan Ilych and its focus is mainly on the inevitably of death, how people deal with it, the frustrations and sufferings of the protagonist, how he himself copes or at least tries to with death, as well as his regrets about a life wasted.
To me, while the book is excellent especially with how well it deals with the character's thoughts about death, him slowly realizing that there is no coming back from what he is suffering and how he first tries to play the seriousness of his disease down. It does that very well.
But there is another element, a universality of Ilych's experience that is evident in the sufferings of people around us and this book just describes it to perfection.
This book starts on a high and just keeps ramping it up!
So, after the great first book, which now looking back, was more of a prologue book setting up and introducing us to the main characters, comes the sequel that takes the best elements from the previous entry and dials them up a notch.
Also, the ending is very poignant. I wasn't expecting a certain character's death to hit me as hard as it did.