Blissful Bookworm Cardigan

Finished Measurements
Bust Circumference: 32 (36, 40, 44 / 48, 52, 56 / 60, 64, 68)" / 81.5 (91.5, 101.5, 112 / 122, 132, 142 / 152.5, 162.5, 172.5) cm
Shown in: 36" / 91.5 cm.
Model measures 40" / 101.5 cm bust, for 4" / 10 cm of negative ease. Can be worn with positive or negative ease as desired. 

Yarn
Worsted (CYCA #4 Medium):
approx 730  (810, 900, 970 / 1065, 1160, 1260 / 1335, 1440, 1570) yards / 668 (741, 823, 887 / 974, 1061, 1152 / 1221, 1317, 1436) meters.
Shown in: Quince & Co. Owl (50% American Wool, 50% Alpaca; 120 yards [110 meters]/50 grams): 7 (7, 8, 9 / 9, 10, 11 / 12, 12, 14) hanks.
Color Shown: Barents sea

Crochet Hook
Size US N/13 (9 mm)
Or size needed to obtain gauge.

Notions
Removable markers; tapestry needle; seven ¾" / 2 cm buttons

Gauge
12 sts and 12 rows = 4" / 10 cm in single crochet after wet blocking (see Notes on Gauge Swatching). Take time to save time, check your gauge. 

Gauge Swatching
With recommended hook size, ch 17, turn. Sc in second ch from hook, then sc into each of the following 15 ch, turn—16 sc. 
Next 15 Rows: Ch 1, sc in each sc to end, turn. Fasten off.

Wet-blocking your swatch before confirming gauge is essential for the proper fit of this garment. This stitch pattern, worked with this yarn weight and needle combination may be likely to stretch and loosen up when washed. 

To wet-block: Soak your swatch in cool water until it’s saturated. Roll it in a towel and squeeze out any excess water. I recommend pinning it to measure about 51⁄4" / 13.5 cm square, then let it dry. It may take some stretching lengthwise to pin to this measurement. Measure gauge once the swatch is completely dry. If you measure 12 sc over 4", you've got the right hook size, if you have more than 12 stitches, try again using a larger hook, or use a smaller hook if you have less than 12 stitches.
When your sweater is complete, wet-block the sweater to the schematic measurements, using the same technique.