Robert Thorne is a historian at Alan Baxter & Associates, and has written widely on architectural and engineering history. He reviews the Frei Otto exhibition (pages 50-51).
John Pardey, who wrote this week's Building Study, is a practising architect based in the New Forest.
He is also the author of Utzon Logbook: Two Houses on Majorca.
Dennis Gilbert arrived in London in the 1980s and is one of the founders of picture library VIEW.
He photographed Tony Fretton's Clerkenwell house on pages 25-37.