If you want to stick to a single textbook ..this is the one to get !<br>It is quite up to date, extremely readable and didactic since it includes key solved exercises which a newcomer to the field needs to go over  (seasoned String Theorists probably would skip over many of them ) .<br>If you are in need of a basic (yet quite comprehensive) S.T. Intro turn to the (affordable) McMahon DeMystified USER FRIENDLY book.<br>I think the  "In a nutshell" and "Polchinski" books are very good too,  but they expect the reader to work out way too many calcs on their own and they  gloss over concepts and calcs that are only obvious to readers with a fair amount of String Theory background. Skipping those calcs can easily mislead the reader into thinking they understand the material ...<br>It's a Mystery why String theory has taken so long to evolve (about 50 years) and is still encountering serious difficulties  (the latest one being the humongous number of available Vacuum states - "Landscape problem")<br>Given the large amount and the high caliber of String Theorists (including Nobel Prize winners) it would be reasonable to expect for the Physics community to delineate the capabilites, limitations and use of the theory ...