Christina L.
Yelp
This is a really cool bar, tucked away in Roppongi off in what seems like a residential area, across the street from Butagumi. Go eat some of the best tonkatsu at Butagumi and then come here to the Library Bar for a post-dinner drink.
Upon walking in, you may think you are in San Francisco or New York - it's a dimly lit, swanky lounge with lots of bookshelves and books, sticking true to its namesake. And by the amount you're paying for a cocktail, you may as well be in SF or NY. Not for the faint of heart - each cocktail will run you about $15-18.
If you don't speak Japanese and the servers or bartenders don't speak English, you can usually get by okay. They will bring you a bowl full of fruit where you'll pick the type of fruit that you want in your drink. Some things you may find: mint, sugarcane, kiwi, passionfruit, pineapple. I made some combination with kiwi and passionfruit and it was delicious; I'm pretty sure there was vodka in there, but I couldn't taste it - it felt like I was drinking juice or eating fruit out of a glass. It's also easy to make weird combinations if you pick the wrong things / too many ingredients, so remember that less is probably more, and you can ask them for recommendations too.
It's a unique experience and would recommend it if you're already in the area and don't mind dropping a little bit of money for a drink. If I come back to Tokyo, I think I'd stick to the more traditional, smaller bars in Shibuya and leave these kind of loungey experiences for the States.