Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Even better now

I earlier reviewed this book while I was in the middleo of it. Now that I finished it I give it four stars. I learned a great deal about world lines and Minkowski's spacetime diagrams. This is such an important concept that Einstien has shunned in the begining but later on used it as the foundation fot his general theory of relativity.The book also has a prologue written in 1996 reflecting on some of the facts stated earlier in the book and new advancements in the field of relativity/quantum physics/cosmology.