This report compiles and synthesizes updated information from various sources on problems and constraints, lessons learned and best practices identified in the process and preparation of national communications and biennial update reports by Parties not included in Annex I to the Convention (non-Annex I Parties). The report will inform the work of the Consultative Group of Experts on National Communications from Parties not included in Annex I to the Convention on the identification and provision of technical assistance to address the needs of non-Annex I Parties, and serve as a source of lessons learned and best practices for those Parties.