This book is an attempt to profile important militant groups presently active in South Asian countries. It leaves out many militant groups that earlier have merged into some larger groups or have been inactive for some years. Nevertheless, the book covers some inactive groups given their potential to regroup and get into action. The information related to these militant groups have been culled from open sources and due care has been taken to check the facts for consistency and reliability. The threat perception from each group has been covered in this book in details. The book will be useful for further research on militancy, terrorism, radicalization and security related issues.