As Katherine noted recently, Oscar has discovered his vertical side. He has not only done the top of her bookshelf, but also my bookshelf, the top of the living room entertainment center and the upstairs hall railing.
There are two slight problems with this new found dimension, especially with the hall railing.
The hall railing was (and is) a favorite vertical escape route from Oscar for the Catzillas, because while no higher than the kitchen counter (a common visit for all three boys), Oscar didn't go up there. Now its utility is lessened, because while Oscar doesn't actively pursue up there, he will visit.
The second problem is that ... well, Oscar is a clutz. Almost every time I've seen him on the railing, a load bearing paw will slip off to the side once as he strolls or turns, and only four paw drive saves him (no claws needed). I swear I've seen him slip more times in a month than I have seen the Catzillas slip in the nearly three years we've lived in the Kitten Farm West. I don't know why Oscar doesn't know where his paws are, but I hope it's youth and lack of practice more than a lack of Spider-cat genes. I also hope he doesn't fall off completely -- an unexpected six foot drop to the stairs, even with them carpeted, would not be fun.