Hello
Pardon my ignorance on this.

I am just starting with calibre and started adding books sequentially (folder by folder to avoid duplication). I have couple of encyclopedia's and engg books which span to multiple pdf's (same book), how to add these as single entity in calibre.
By adding them thru folder option calibre creates multiple entries in library , which are not inter related at all..
can someone please guide me how to go about on this.. Thanks
Attaching SS:
above is an Britannica encyclopedia spanning 7 volumes, but all have been added as separate books.