Hello

I am looking for a book on the Pico 8 or tutorials thank you

You can certainly buy the PICO-8 digital magazines and read them offline on your computer or transfer them to your cellphone, tablet, or other media device as they are PDF in format.

They are totally worth the cost of purchase, Bernard65. And if you don't know how to convert British pounds to American, just put in $2 for each to make it convenient. :)

https://sectordub.itch.io/pico-8-fanzine-1
https://sectordub.itch.io/pico-8-fanzine-2
https://sectordub.itch.io/pico-8-fanzine-3
https://sectordub.itch.io/pico-8-fanzine-4

Here is the table of contents for the first magazine:

 3 ... A Brief History Of Pico-8
10 ... Squashy
22 ... Let's Make Some Music
30 ... Toy Train
38 ... Geodezik
39 ... Smoke Particle
43 ...Welcome To Pico-8 !

You can find the PICO-8 Fanzines here:
https://sectordub.itch.io/pico-8-fanzine-1

Game Development with PICO-8 - Issue 1 by MBoffin:
https://mboffin.itch.io/gamedev-with-pico-8-issue1

You can find a list of resources compiled by @platformalist here:
http://pico-ate.com