Add a support for loading PDF file format into DocumentModel.
Mario at GemBox
This feature request has been implemented and is available in the latest versions of GemBox.Document.
Regarding the merging of multiple PDF documents, for this, you should consider using GemBox.Pdf instead.
PDF reading is a much more intensive task than PDF writing and actually, we first want to improve the support of existing formats.
Please note that one of the options that we think about in the long term plan is implementing a PDF reader, however, since it is a very extensive task you should not expect this feature to release in the next year (unfortunately even dough we do realize it is a high demanded feature).