Squashed 'book/sca/' content from commit 89d78f2

git-subtree-dir: book/sca
git-subtree-split: 89d78f256885fe62b3d5707a7dbbcac4b37d340b
Merge commit 'c0496885c53fc41bc36109154a7e5b8b23a06652' as 'book/sca'