Vintage Mystery Challenge 2018: Just the Fact's Ma'am...

I'll try again

Hosted here

Challenge Levels
Constable: 6 books — one from each category
Detective Sergeant: 12 books — two from each category
Inspector: 18 books — three from each category
Chief Inspector: 24 books — four from each category
Superintendent: 30 books — five from each category
Chief Superintendent: 36 books — six from each category
Deputy Chief Constable: 42 books — seven from each category
Chief Constable: 48 books — all eight books from each category

Pre-1960

1960-1989 (inclusive)

My goal is Detective Sergeant