This latest volume of the National Gallery's Technical Bulletin series features a range of studies, reflecting its commitment to the scientific research and conservation of paintings in its care. Articles include the recent conservation of Rosso Fiorentino's A Knight of Saint John ; the historic technical literature in the Eastlake Library; the use of macro XRF scanning to inform the conservation strategy for Ferdinand Bol's An Astronomer ; and newly discovered structural modifications and pictorial changes in Jacob Jordaens's Portrait of Govaert van Surpele and His Wife . The revelatory insights into the collaboration between Sebastiano del Piombo and Michelangelo garnered through the use of infrared reflectography amplify the discussion previously published in Michelangelo & Sebastiano (Yale). Published by National Gallery Company/Distributed by Yale University Press.