Heinrich Biber s astonishingly powerful and deeply emotional Mystery Sonatas represent a triumph of Baroque invention. Boston Baroque s Christina Day Martinson delivers a technical tour de force, as she navigates the virtuosic challenges presented by the fiendishly demanding changing scordatura. Boston Classical Review described her live performance as a flourish of technical complexity and musical wizardry , whilst the Boston Globe wrote, Day Martinson...didn't just survive, she triumphed. The adventurous use of six baroque violins in fifteen different tunings creates otherworldly soundscapes that result in a deeply moving and glorious listening experience. This highly disorientating practice reaches its pinnacle in Sonata XI ('The Resurrection') where the middle two strings are crossed over each other both in the peg box and behind the bridge, so that one can literally see a cross on the violin. The fifteen sonatas have been traditionally grouped into three sets of five: five joyful mysteries, five sorrowful mysteries, and five glorious mysteries. Boston Baroque s founder Martin Pearlman plays organ and harpsichord, with Michael Leopold on theorbo and guitar and Michael Unterman on cello.