> I'm 35 and I have probably seen an actual contact book only once when I was little.

This just seems weird to me. Contacts books were replaced in a very limited way by PDAs for early adopters, but it wasn't until smartphones and their easy address books that they really started to die off. So post-2008, really.

Were you not in professional settings until your late 20s? Still be surprised if you are both 35 and genuinely unaware of what an address book is.