According to the author of History of 20th Century Fashion, it was the tailored jacket which gave rise to the delicate lingerie blouses like PP404, PP405 and PP406.
This double breasted jacket is very easy to make. Even the pad stitching in the collar is machine sewn.
The pattern is multi-size 10 to 18. All Sizes use 2-5/8 Yds. fabric. The original was made of fine textured lamb's wool. Wool is the preferred fabric because it has stretch and will shape at the waist better than cotton, silk or linen.