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).