Sans-serif in Alain de Botton book covers

Does anyone know which sans-serif typefaces are these on Alain de Botton book covers?

http://twitpic.com/7hffqk

Comments

"Alain Botton" must be Verlag Black
"Como Proust" looks like Verlag Book

http://www.typography.com/fonts/font_styles.php?productLineID=100009

Thank you, fvilanakis!