I bought my Harry Potter books from Amazon, which is where I buy most of my books, both physical paperbacks and Kindle eBooks. Amazon always helpfully suggests books it thinks I might like, based on my interests in a section titled 'Books you may like'.
This generally reflects my normal preferences - normal that is for a 64 year old bloke with a wide range of interests, slanted towards science, technology, aviation, computing and science fiction.
I went on Amazon again tonight after my recent purchase of a boxed set of the Children's edition of Harry Potter books 1-7, chosen partly for the cheery covers, and also because despite containing exactly the same content, the children's edition was £31.50 and The Complete Collection (Adult Paperback) was £45.56
As usual Amazon offered me a selection of books it thought I might like - see screenshot below, but it seems to have been more than a little influenced by my purchase of the Childrens Boxed Set, - as it is now peppered with books like 'Why is SNOT green', lots of Jokes & Riddles, Train your Angry Dragon, Treasure Island, Biggles delivers the goods, White Fang, Unicorn Rescue and The Squirrels who squabbled.
I have a feeling it might be a while before Amazon offers me its previous well considered, and accurately targeted 'Grown up' version of - 'Books you may like' - In the meantime, I've bought a copy of 'Why is SNOT green'. After all - with the current COVID-19 pandemic, you never know - it might come in handy.
STOP PRESS - by the miracle of modern technology, my latest purchase was wirelessly delivered to my Kindle - and as I'm sure you're all dying to know - I can now reveal why snot is green.
I found it on page 138. Apparently the nose contains a sticky substance which traps and flushes out harmful bacteria, and cells that the body produces to fight and kill the bugs - it is these special proteins called lysozymes that make your snot green.
I didn't know that - you're truly never too old to learn :-)