Mafia: Definitive Edition features numerous different collectibles, including magazines, comics, cards, cars, and foxes, all of which are required to get 100% completion in the game. A total of ten Gangsters Monthly comic books can be found dotted across Mafia: Definitive Edition, with four available through the story and six available in Free Ride.
None of the collectibles in this game can be permanently missed, meaning that if you don't pick up a comic book during your playthrough, you will still be able to collect it via chapter replay. Once you pick up a comic, it is instantly saved to your profile, meaning you do not need to complete the chapter or reach a checkpoint for it to be saved — you can back out immediately if you want. You can view which collectibles you are missing in the Collection Menu and arrange them in order of how they chronologically appear. This Mafia: Definitive Edition comic books guide will list them in order, so you can cross-reference and determine which ones you have missed.
Mafia: Definitive Edition Comic Books Guide — Story Mode Comics
Mafia: Definitive Edition Comic Books Guide — Chapter 8, Sarah Moll On A Mission Comic
In Chapter 8, "The Saint and the Sinner," head up to the third floor of Hotel Corleone and take a left. Go to the far end of the hall, turn left and make an immediate right into the first door (to Room 210). Head into this room's bathroom, take down the guy inside and you will find the "Sarah Moll on a Mission" comic book sitting on a cabinet to your left.
Mafia: Definitive Edition Comic Books Guide — Chapter 10, A Trip to The Country Comic
In Chapter 10, "Omerta," you will eventually come to a bank. Head through the doors at the far end of the lobby and head downstairs. Once underground, you should pass a guard on your left. Turn immediately right when you reach him and you should see the "A Trip to the Country" comic book on a red chair.
Mafia: Definitive Edition Comic Books Guide — Chapter 15, Steam Boys comic
In Chapter 15, "You Lucky *******," you will pass a large red crane while chasing Sergio. Head past the crane and immediately turn right, hugging the base of it. Enter the train car directly in front of you (the one with the three wooden crates in front of it) and you will find the "Steam Boys" comic on a box to the right.
Mafia: Definitive Edition Comic Books Guide — Chapter 20, Moonlighting
In Chapter 20, "The Death of Art," climb to the very top floor of Paulie's apartment building. After the last set of stairs, take a right and head straight, all the way to the end of the hallway, where you should find the "Moonlighting" comic book waiting for you on a small side table.
Mafia: Definitive Edition Comic Books Guide — Free Ride Comics
The first comic in Free Ride can be found in North Park. Drive to the far east end of the road directly above the "North Park" text on the map. Speed west down the street and as soon as you reach the intersection, swerve slightly right so that you are driving west on the upper platform (to the right of the pink flowers). Hit the ramp at a slight angle so that you land on the roof of the diner ahead and to the right. The "The Mafia Three" comic can be found on the corner of the roof near the "DINER" sign.
On Central Island, head as far north as possible, up toward the State Prison. Head down the east alley to the side of the prison and climb over the chain link fence near the far end, in the spot that is barbwire-free. Follow the dirt path around, towards the south where you can find the "Jimmy's Vendetta" comic in a pile of trash on the ground, against the prison wall.
North of Works Quarter, in the northwest corner of the intersection above the "Works Quarter" text on the map, you should see a brick wall in the parking lot with numerous "Tire and Accessories" and "Stop and Gas With Us" banners. Climb over the rightmost "Stop and Gas With Us" banner and head to the back left corner of the grass area. Sitting in front of a wooden bench by the wooden building will be the "All Saint's Day Massacre" comic.
Head to the Chinatown area of the map. If you look very closely, you should see an alleyway hidden behind the "H" in "Chinatown". Head to the entrance to this alleyway and you should see a trash can on the right side, at the corner of the building. Behind this trash can is the "The Racing Racketeer" comic book.
On the west end of Terranova Bridge, head to the south side of the bridge and down to the shore. Just to the east of the only building that appears on your map, you should find a small shack with a wooden deck. Enter this shack and head out onto the deck to find the "Beware Hanoi Hangman" comic book next to the folding chair.
At Clark's Motel, just south of Lake Nahawa in the northeastern area of the countryside, head through the right gate and climb up the wood stacks to reach the upper balcony. Sitting on a table up here will be the final comic, "An Offer You Can't Refuse".
Now that you've got all ten of the Gangsters Monthly comic books, you should unlock the "Picture Book Connoisseur" achievement or trophy and are one step closer to completing the game.