In order to capture current educational practices in eLearning courses, more advanced "learning design" capabilities are needed than are provided by the open eLearning specifications hitherto available. Specifically, these fall short in terms of multi-role workflows, collaborative peer-interaction, personalization and support for learning services. We present a new specification that both extends and integrates current specifications to support the portable representation of units of learning (e.g. lessons, learning events) that have advanced learning designs. This is the Learning Design specification. It enables the creation of a complete, abstract and portable description of the pedagogical approach taken in a course, which can then be realized by a conforming system. It can model multi-role teaching-learning processes and supports personalization of learning routes. The underlying generic pedagogical modelling language has been translated into a specification (a standard developed and agreed upon by domain and industry experts) that was developed in the context of IMS, one of the major bodies involved in the development of interoperability specifications in the field of eLearning. The IMS Learning Design specification is discussed in this article in the context of its current status, its limitations and its future development. (Contains 3 figures.)