The famous Dutch architect Rem Koolhaas, the mind at the center of the Central Library, will speak to Seattle about something it needs more of: "Public Space." Is there any way to get enough of this, Koolhaas? No. He's a great writer, theorist, and speaker. As for his book S,M,L,XL, it's the bible for an age that has lost all sense of gravity. We now float from hip to hip, from dip to dip, from building to building. (Central Library, 1000 Fourth Ave, 386-4636. 2 pm, free.)