States are the primary subjects of International Law. In general, there might be some questions about States for instance; what is a State or when an entity regards as a State on the International plane? States might come to existence, merge or dissolve. Further, State recognition regards as the most important and complicated matter of International Law. Consequently, this book, intended to evaluate the issue of State Recognition. Primarily, Recognition of States and governments is illustrated. It started with the "constitutive and declaratory" theories on the nature of State recognition. Hence, it focuses on the recognition of governments. Moreover, the modes of recognition are clarified. Besides, Kurdistan Regional Government as a de facto State and their interest to formulate an independent State is discussed. Thereafter, is illuminating the forms of recognition. Lastly, the legal effects of recognition in International and municipal law "UK" experience is determined. This Study will help International Law students and researchers to understand the significant of recognition matter for an entity to be a State.