With the massive amount of captured multimedia, authoring is more relevant than ever. Multimedia content is available in many settings including the web, mobile devices, desktop applications, as well as games and interactive TV. The authoring and production of multimedia documents demands attention to many issues related to the structure and to the synchronization of the media components, to the specification of the document and of the interaction, to the roles of authors and end users, as well as issues concerning reuse and digital rights management. Several complementary approaches to support the authoring of multimedia documents have been reported in the literature, and in many cases they have been studied via authoring tools and applications. One aim of this special issue is to assess current approaches, tools and applications, discussing how they tackle the main issues relative to the process of authoring, as well as their limitations.