Pre - Online Policing

I’m continuing my nostalgic re-read of Ngaio Marsh's murder mysteries. This one was published in 1968 and it’s a reminder of a pre - technological, pre-online world.
 
The detective who heads the investigation, Superintendent Roderick Alleyn, carries in his pocket an insufflator (for dusting finger prints) and a magnifying glass. When he finds a tyre mark, he measures it and makes a sketch of it. More Sherlock Holmes than modern police investigation.
 
Another glimpse of an almost forgotten era is the order form at the back of the book. If you want more Ngaio Marsh novels, just cut out the form, list the titles you want to order and attach cheque or postal order and post it to the Isle of Man. Don’t forget to include 8p per title for postage.
 
One further image from a vanished world. The story is set on a river cruise boat. At one point a male member of the party decides to take a dip. So he dons his ‘swim slip’. My grandfather had one of those, and it was a great deal more modest than your average speedos.