404. That’s an error.

The requested URL /books?op=add&sig=rR7XMN17j1neU-d8kLaaH-lHdl0&as_list=BDQXMCQsQhZin2PDs2NtGGhRyMV9Z2itOShQEzIO_iASbLYz3dg&id=EBk8gNKWKtIC&continue=http://books.google.com/books%3Fq%3DPippa%2BNorris%26lr%3D%26as_brr%3D3%26start%3D0%26hl%3Den was not found on this server. That’s all we know.