The sentence means that the book is about the idea of self-sacrifice and implies that the subject is a difficult one but that the book rises to the challenge. The sentence is intelligible and doesn't contain any grammatical errors; however, I would word it differently. Firstly, "tackled" is in the past tense. This sounds a little strange to me because reading a book is an experience. If I describe a book to someone presumably he hasn't yet read it, so the experience is not in the past for him. I think this is why it is more natural to say "This book tackles the idea of self-sacrifice." "Tackle" is not the word I would use, either. It is true that one might "tackle a problem" meaning to overcome it, perhaps with some struggle. This doesn't sound quite right to me for a book, even if the subject is a difficult one. I might use "take on" (This book takes on the idea of self-sacrifice.) and leave it to the other person to decide whether the book succeeds, but I am much more inclined to use words like "explore," "explain" or "discuss" when the object of the sentence is "idea."

Hi Pasha, Yes, the sentence makes sense -- it is actually a common way for book reviews to introduce the topic of a non-fiction book if the topic is sensitive or complex. In contrast to Hiroshi, I find the use of "tackle" in the past tense to be natural as well -- it may mean the book was published a while ago or is distant from the speaker in some way.

yes, it is clear