BradyGames’ XCOM: Enemy Unknown Official Strategy Guide includes the following:

Our Last Hope

Earth is under siege. Only XCOM has a chance of preventing humanity’s extinction. Confront this infestation wherever they threaten, research alien technologies, and defend your home.

Mission Debriefing- Be prepared to tackle any mission the Council throws at you. We’ve built flexibility to adapt to any given mission into the walkthrough, because the XCOM story arc is randomly generated from event to event.

Tactical Multiplayer - Build an effective fighting force with our squad creation tutorial, and then take that force online to challenge your opponent.

Research Lab:

Xenobiology

Preparation is your best weapon. Our alien encyclopedia is tied into the other components of the research lab. It includes data and stats for the various life forms, from the sneaky Thin Man to the dangerous Cyberdiscs.

Advanced Engineering

Your ignorance is the alien’s most potent weapon. Discover how technologies, aliens, and equipment are tied to equipment creation, ship advances, and base structures. All the information you need on every item and piece of equipment in the game is at your fingers.

Weapon Manufacturing

Weapons and armor suits are the keys to your survival. Outmanned and outgunned from the start, learn how to get the best weapons and armor without wasting money or time.