We talk to German artist Anselm Kiefer about his new works inspired by String Theory and ask expert Scott Reyburn why the art market is treading water. Produced in association with Bonhams, auctioneers since 1793

How a work of art comes to auction is far from a simple process and its place in the eventual sale order is crucial

One of the works was looted by the Nazis from Jewish collector Jacques Goudstikker, but is now being sold by his heir after restitution