Perception

Perception Training

Perception is a SPECIAL attribute that constitutes to your environmental awareness, allowing you to detect threats at a much farther range (they'll appear as red dots in your radar) and your weapon accuracy in VATS.

Pickpocket

This perk allows you to effectively sift through another character or NPC's possession or inventory with lesser risk of getting detected. This is perfect for stealth-based character builds since they'll be able to sneak to get near their targets. Pickpocketing is not always for taking things. At Rank 2, you'll be allowed to place live grenades to your target's inventory, effectively killing him/her instantly in an explosively messy glory.

Rifleman

This perk improves both ballistic and energy weapon damage of non-automatic rifles, as well as their ability to ignore a percentage of the target's armor rating.

Awareness

This single-rank perk augments your VATS screen and displays the target's damage resistance type, allowing you to switch to weapons they're weak against.

Locksmith

This perk allows you to pick higher difficulty locks, safes, or doors. This is quite an important Exploration skill since the good stuff or alternate routes are usually found behind these locked containers or doors.

Demolition Expert

This perk increases the damage of explosive weapons such as grenades, mines, missiles, and mini-nukes. For heavy weapons such as Missile Launchers and Fat-Man, this perk's bonus stacks up to the Heavy Gunner Perk which also increases the damage of those weapons.

For some reason, pulse mines and pulse grenades are not affected by this perk. Additionally, if the grenade / mine can deal two types of damage, the secondary damage will not be increased.

Night Person

You a creature of the night! This perk gives you considerable boosts to Intelligence and Perception at night.

Refractor

This perk increases your character's damage resistance against energy-based weapons (plasma and rifle)

Sniper

This perk is for players who prefer sniper rifles as their weapon of choice most of the time. The perk provides helpful enhancements like accuracy and focus.

Penetrator

This perk allows your projectiles to go through solid objects while targeting them in VATS. That means you can destroy the fusion cores of sentry bots or enemies wearing Power armor even when they're facing you. As long as the part you want to hit is visible, you should still be able to see them through VATS.

Notable, ballistic and energy projectiles seems to be the only projectile types that can take advantage of this perk. Solid obstacles can still shield the enemy against explosives like grenades, missiles, or mini-nukes.

Concentrated Fire

This perk abuses your AP stock so having a good Agility rating will ensure that you'll have as many consecutive shots your AP and weapon allows. Concentrated Fire increases your accuracy in VATS by targeting the same body part.

Images courtesy of Fallout Wikia.