There is a wealth of information online on the process of bookbinding. The information here is specific to the volumes in the Western Australian Exploration series.
Sixteen pages of a volume are gathered together as a ‘section’ and placed inside another 16 page section. This 32 page section is then sewn together with book binding thread. All the 32 page sections that make up the volume are then sewn together as one ‘block’. A gauze type fabric is then glued to the spine of this block to further reinforce it.
Endpages are then glued onto this block (the entire text of the volume) and the case binding (or hard cover) is glued to the Endpages. It is interesting to note that the spine is not glued into the case binding, just the Endpages. This allows the volume to be opened flatter and ensures that the spine will not crack.
The case binding is covered in a ochre coloured linen paper.
Section sewing creates a book that is very durable, opens flatter, and is easier to read.