I second this, the SF Public Libraries are a great place to work. I used to work out of the Potrero Hill branch a lot. The main library (the one by the Civic C

I second this, the SF Public Libraries are a great place to work. I used to work out of the Potrero Hill branch a lot. The main library (the one by the Civic Center) closes way later than the rest. Good spot if you're working alone.