This book is a good introduction to IR theory for novice or if you want to refresh your memory of IR Theory that you learned many years back, I mean many years back--speaking of myself here.
This book divided by two segment:
1) Established theories i.e. Realism, Liberalism, The English School, Constructivism, Marxism, Critical Theory, Poststructuralism, Feminism, Postcolonialism, Towards A Global IR; and
2) Expansion pack i.e. Green Theory, Global Justice, Queer Theory, Securitisation Theory, Asian Perspectives, Global South Perspectives, A Contemporary Perspectives, The 'isms' are evil, hail the 'isms'!
While it's reasonable to only read theory or theories that you want to know, nevertheless it's still worth the effort to read this book in its entirety. The team behind this book project did a great job, KODUS!