Fallout 4's character system has been explained by Bethesda.
"At the heart of Fallout 4 is its character system," the developer says. "Our games are about making the kind of character you want, doing what you want, and having the game allow and reward whatever playstyle you chose. We also want to make those choices meaningful, and at the same time entertaining. To let you plan ahead, try different things, and to compare your choices against others who built different characters."
The studio says they want SPECIALs to be as meaningful as possible and has developed a guide to help you plan how your character will develop.
SPECIALs are the first decision you make, rating them from 1 to 10. The SPECIALs are Strength, Perception, Endurance, Charisma, Intelligence, Agility, and Luck which effect how various events happen in the game and your dialogue options with NPCs.
28 points can be assigned initially, making it difficult to max out some SPECIALs, but you will be able to start with a 10 by neglecting others.
You choose these before entering the Vault but can change them once you're out. Levelling is similar to Fallout 3's XP system but the rate at which you level is closer to Skyrim.
Fallout 4 also has no level cap.
When you level up, you select a Perk, which are charted below:
