The study presents results of many years of research and analysis into the process of creating core textbooks and teaching materials aimed at developing linguistic, communicative and professional competences inherent in the future professional activities of International Law students. When creating language learning materials with a focus on a particular profession (e.g. English for Law Students), it is important to proceed from the nature and specific content of day-to-day activities surrounding the future job of a student. Detailed analysis of legal documents and professional activities that International Law students may be involved in in the future allows to gauge the necessary level of English grammar and vocabulary that needs to be attained. The process also points out what specific language and communication skills (e.g. negotiation, persuasion, etc.) as well as professional competencies may be required. Since core textbook for learning English written by native speakers are very generic and, naturally, do not aim at achieving the level of English language, communication and professional skills required by those specializing in International Law, we find it of vital importance to create a series of very niche textbooks for achieving these goals. The present study allows us to determine the structure and content of core textbooks and to create a system of grammar and lexical exercises as well communication tasks aimed at acquiring specific grammar and conversational skills within a short period of time. Of particular mention here too is mastering debating skills, which is paramount for International Law students. This again can only be achieved by creating very narrowly focused materials that will introduce these skills gradually.