This book has no pretention to propose a new typology of International Parliamentary Institutions (IPIs). As we have seen in the introduction, many authors have elaborated such typologies. They are very interesting and a useful tool for analysis, but every exercise of classification has its own limitations: it implies choices that highlight some aspects of the cases under study (name, structure, membership, competences etc.), and necessarily hide others. We also consider that the phenomenon of IPI is still too new and evolutionary to propose a definitive classification. In that respect, it is interesting to note that academic research has an impact on institutional practices: it has already contributed to clarifying a bit the landscape of IPIs, and will continue to do so, since actors of IPIs are curious about other experiences in the field of parliamentary integration and about academic work on that question.