I think what you are asking is Taihu Book City (Beijing Publishing Logistics Hairstyle Center). You can take bus No.938, No.6, No.372 and No.647 to Liyuan, and look for the stop sign of Xiaoqi Road at the intersection of Liyuan Road. You can take Xiaoqi Road directly to the gate of the Book City. This route is my last visit, but it's too big to visit all day. Good luck buying books!