I really  am enjoying reading this book. The perspective on history I find gives the book a life many other books don't have. The conversational tone is very appealing to me and things are really presented clearly most of the time. Sometimes steps were left out and assumptions were made about what a steps a person could fill in on his own.  But with no answers, the book was at times frustrating (and hence four stars). Still, I liked the book. Another book written in a conversational tone with a lot of intution, but which does subsequently get rigorous, is Sultan's "A Primer on Real Analysis".  He covers some different, higher level topics and it is well written.  In addition it has answers which is a big plus. For me, the two books are are a good combination.