This is a nice book to have if you're trying to learn string theory. The presentation is rather straightforward. What's really nice is each chapter has several solved examples. But best of all the writing is clear and its relatively (no pun intended) easy to follow the book to the end. In my opinion, this book is accessible to anyone with a basic physics (or even math) undergraduate education. Zweibach is a great book for sure, but by design it cuts corners in an attempt to make the subject accessible to undergraduates. I don't think thats really necessary (except maybe avoiding path integrals). What I like about this book is it does not cut corners. Topics that are avoided in Zweibach are definitely discussed in here.