I have almost finished reading the basics of Bosonic String Theory from Becker, Becker and Schwartz as well as Tong's notes.
What is the best book to start reading about Superstring theory (something which is slightly easier than Polchinski). I am confused among these options:
String theory is an enormous subject. Even the very notion of "what is the minimum" desirable knowledge is diffuse and strongly depends on what exactly motivates you to learn string theory.
However, general suggestions can be made:
It's a really good idea to have the excellent Blumenhagen-Lüst-Theisen textbook "Basic concepts in string theory" in mind. All the details of many important constructions and computations are worked in an incredibly explicit way.
The Ibáñez-Uranga textbook String Theory and Particle Physics: An Introduction to String Phenomenology also offers concise and very readable introductions to the subject.
As a personal suggestion: If you are really interested in string theory. At some moment you should take the wonderful adventure of reading Polchinski or Kiritsis. I urge you to take the extraordinary "Introduction to Conformal Field Theory: With Applications to String Theory" Blumenhagen-Plauschinn book to gain the necessary solid knowledge to perform worldsheet computations.
I hope you enjoy your adventure towards string theory.
As Ramiro Hum-Sah already mentioned, string theory is a very broad topic and really the notion of minimality has to do with personal taste.
I enjoyed self-studying and solving the string theory book by Becker-Becker-Schwarz. The title is String theory and M-theory. Some people have the argument that the authors pass really quickly the basic and introductory parts to move on to recent developments. While I see their point, I still think it is a nice exposition.
The reason that I like this book so much is simple. It kind of forces the reader to take pen and paper and go through all the small details. Plus it has some of the cool developments. Combine that with the solved and the homework problems and this is really my top choice.
As a supplement to the said resource, I used the oldie but goldie Superstring Theory book by Green, Schwarz, Witten. Mainly when I wanted more intuition and a more physical explanation, or when I felt that I wanted some more to the contents of my basic book.
To be honest, I consulted some more sources, but these were the main two.
The above are of course personal choices and preferences.
