This is a comprehensive overview of Parmigianino’s enigmatic painting of The Madonna of the Long Neck. It treats the subject in terms of iconography, semiotics, studio practice, and art theory. The painting is not merely an example of mannerist extravagance, but that the Virgin in her extraordinary distension can be explained by a litany in Ecclesiasticus, with her enlargement read as a signifier of her mercy. Parmigianino’s panel is interpreted as an Immaculate Conception. Because the magisterium had not fully defined the belief as dogma, the theological debate confused the artist and his contemporaries, but also gave them flexibility in their depictions of this abstract doctrine. The subject’s genesis as a theological exercise is traced through the artist’s drawings. Illustrations in full color and b&w.