This book deals with the practical application of e-lexicography as a fundamental teaching tool in English for Special Purposes (ESP) classes in the field of law. It is very much interdisciplinary, covering the fields of lexicography, metalexicography, law, ESP teaching and linguistics. It begins with a look at the methodology undertaken during a detailed piece of research conducted by the author amongst several hundred predominantly law students at the Friedrich-Alexander-Universität Erlangen-Nürnberg. The initial aspects addressed in this work revolve around dictionary ownership and usage among the students, as well as technological issues such as Internet access in the teaching environment and the ownership of the requisite hardware which enables students to be able to make full use of online lexicographic tools. It continues with a meticulous study into the inclusion and lexicographical portrayal of approximately 700 specific legal lexical items in the five leading online pedagogical dictionaries for learners of English, the so-called ‘Learner’s Dictionaries’. From both a metalexicographic and a practical lexicographic standpoint, it thoroughly examines the use of diatechnical labelling in general and, more specifically, in the subject field of law, considering as it does the requirements of the dictionary users at every juncture. The metalexicographic and lexicographic analysis ensues on every level of each of the dictionaries, from the macrostructure to the microstructure with mediostructural elements incorporated too. The subject matter is approached form a critical viewpoint and the final components concentrate squarely on detailed proposals for supplementing and amending the online dictionaries, in terms of lemma stock, the micro- and the mediostructure, in order to create a pedagogical dictionary for English learners which could be used more extensively in legal ESP classes and, with additional expert supplementation at the hands of terminographers, in other specialist fields too.