? DoesP=NP. In just ?ve symbols Dick Karp -in 1972-captured one of the deepest and most important questions of all time. When he ?rst wrote his famous paper I think it s fair to say he did not know the depth and importance of his question. Now over three decades later we know P=NP is central to our understanding of compu- tion it is a very hard problem and its resolution will have potentially tremendous consequences. This book is a collection of some of the most popular posts from my blog-- Godel ] Lost Letter andP=NP--which I started in early 2009. The main thrust of the blog especially when I started was to explore various aspects of computational complexity around the famousP=NP question. As I published posts I branched out and covered additional material sometimes a timely event sometimes a fun idea sometimes a new result and sometimes an old result. I have always tried to make the posts readable by a wide audience and I believe I have succeeded in doing this.