I inherited it. I think it dates from the '70s or earlier. It's pretty grubby but I can't bear to part with it.
Your dog is definitely spoiled. I talk to the cats but I don't read to them (they'd get bored and go to sleep), and I don't think they'd care to play in the bathtub, at least not if there was water in it. But it sounds like fun to play in the tub with a big dog.