Bookmatching is the process of joining two sequential slabs together so that they mirror each other in grain appearance giving the impression of the symmetry of an opened book. We rip and joint a straight edge on one side of each slab and glue them together, creating a larger slab around twice the width of each original.
You have the option of matching two or more sequentially cut slabs, or non-sequential slabs. Non sequential slabs will not have the afformentioned symmetry but still offer an attractive look while getting the width you need.
Bookmatching is generally used when we cannot provide a slab that is wide enough in the requested species. By joining two or more slabs together we can produce a surface with a width far exceeding that of a single slab.