From the Patternworks website:
This easy-to-wear vest begins at the back hem, is knit up and over the shoulders, then down each front panel.

Sizes: 35 (37.5, 41.25, 45.25, 49 ,53)“
Yarn: Meadow Silk #234 4 (4, 5, 5, 5, 6) skeins (200 yards per 100g skein)
Needles: #8 straight or circular; and cable needle
Notions: One 1” button
Stitch pattern: Written
Skill level: intermediate

Also available as a kit from Patternworks.