Gauge for ribbing
20 sts/26 rows = 4 inches in rib pattern, slightly stretched

From the pattern description:

This is a magic jacket. Half the members of my knitting circle tried it on – women of very different shapes and sizes – and each one looked better than the last. The combination of simple waist shaping, all-over ribbing, cables and the angled centre panels pull it in while allowing plenty of stretch, making it sit beautifully on every body. And knit in a warm, soft alpaca blend, it’s a wonderfully cosy, stylish way to wrap up on a chilly autumn day.

When working the front pieces, most of the time there are 3 things going on at once: matched increases and decreases every RS row to make the centre panel sit at an angle; cabling the centre panel every 6 rows; and shaping the waist. If in doubt, just remember that the cables and angle shaping carry on exactly as established at the start, regardless of what’s going on with waist, armhole or neck shaping. (The back is simpler as there is no angle shaping to worry about.) Because there is so much going on, you need to pay close attention; I strongly recommend reading ahead and highlighting the instructions for your size.

Because of the pattern’s giving nature, instructions for only 4 sizes are given – trust me, this is plenty. If in doubt go small.

Note: for discussion of yarn substitution, with animal-fibre-free suggestions, see designer’s blog post.