All Stray notebooks locations in The Slums
If you wish to see the outside again, you'll want to collect all of the Outsider's notes.
In Stray, the four notebooks in question are those belonging to a quad of robots known as the Outsiders. These robots have made it their lifes mission to try and reach the outside again, albeit with little luck. Although, this is where you - a four legged feline - steps in to help.
The four notebooks belong to that of Momo, Doc, Clementine, and Zbaltazar. In combination, they all possess plenty of notes regarding getting outside, and will hopefully lead to you being able to communicate with higher levels in this strange world.
This isn't without some leg work, however, which should be no problem because you're a cat. It's finding the books themselves that's the troublesome part. So, here's where to find all four of Stray's notebooks across The Slums.
Where to find all four notebooks locations in Stray
Momo's notebook
When you first arrive in The Slums and speak with the Guardian in Stray, they'll advise you to go find Momo up in the rooftops. They, too, have been trying to make it to the outside world, just like you.
Momo's house is marked by a large, bright yellow neon sign. There's multiple different routes to take, so I advise platforming away and exploring The Rooftops on your way to Momo. Who knows what memories or Sheet Music you may find?
The easiest way to get to Momo's is by climbing atop Dufer Bar, and then simply heading upwards towards the large sign.
When you finally reach Momo, speak with them. They'll tell you all about their lost hopes of reaching the outside, and will lament the loss of their friends, too. Soon enough, they will give you the first of the four notebooks, and will request that you come back once you've been able to find the rest.
Clementine's notebook
Leave Momo's flat from the way you came in, and B-12 will point out the Outsider logo to you. This logo is on all three of the other flats you need to find, and will help you if you get a little lost.
That said, B-12 just showed you Clementine's flat. Take the zip line bucket and hop straight over across the rooftops. The route is super straight forward, and after traversing a pipe, you'll enter the apartment from the window.
At the back of the apartment, go through the broken glass doors and into the small office-like room on the left. By the PC, Clementine's notebook can be collected!
Doc's notebook
Next, we want to go and grab Doc's notebook. Exit Clementine's apartment and make your way to the left, over towards the rooftop sofa that sits near a sleeping robot.
If you face the sofa, you can see the entrance to Doc's apartment is just behind.
Make your way inside, and locate the small back room. The entrance to the room is blocked by books that you can topple over to your hearts content. Inside the room, collect the small note and the keys on the bed.
The note will inform you that a safe is hidden behind a stack of books in this library-like abandoned home. Make your way to the middle set of shelves, where books beginning with M and L live. Knock over the piles of books here and the safe will be revealed.
Use the keys that you just picked up to open it, and Doc's notebook will now be yours to collect!
Zbaltazar's notebook
For Zbaltazar's notebook, leave Doc's flat and head straight. You'll be able to see the logo for the Outsiders from Doc's.
Jump across the rooftops and past the robots who are playing with paint cans. Once you reach the blocked off balcony for the flat, make your way to the rooftop above it. You'll find a ventilator here.
Remove the plug for the ventilator from the socket, and it'll stop spinning. You can now jump through the powered-off vent and into Zbaltazar's flat. In the flat, you'll see three piles of boxes. Jump on top of these to knock them all over.
Once you've made a real big mess of Zbaltazar's flat, you'll find their notebook on the floor somewhere, having fallen out of one of the many boxes. If you're struggling, move the boxes around a little until you find it.
At last, you have all four notebooks from The Slums, and can go report back to Momo with them!
For more on Stray, make a point of collecting all of B-12's memories, as well as all of the Vending Machines across The Slums, too!