Here's a roundup of sections in the book (incomplete, the person stopped at the early NR era):
There are pages for many planets, and a species section, as well as history lessons by era.
Maps in the Atlas:
The Galaxy (generic dateless)
The Core
The Colonies
Galactic Population c. 25 ABY
The Inner Rim
The Expansion Region
The Mid Rim
Hutt Space
The Outer Rim
Client States and Miscellaneous Regions
The Rakata Empire c. 30,000-25,200 BBY
The Conquests of Xim the Despot 25,127-25,096 BBY
The Pre-Republic Galaxy c. 25,100 BBY
Origins of the Jedi (and other mystic traditions of the young Republic) c. 25,000-22,000 BBY
Galactic Explorations (basically a pre-Naboo timeline of such, most colorful map in the Atlas)
The Sith Empire c. 5,000 BBY
The Great Hyperspace War c. 5,000 BBY
The Great Sith War 4,000-3,996 BBY
The Jedi Civil War 3,959-3.956 BBY
The Mandalorian Wars 3,976-3,960 BBY
The Fall of the Republic 1,004-1,000 BBY
The Hapes Cluster
The Hydian Way c. 3,693 BBY
Sidious's Preparations 52-32 BBY
The Phantom Menace
The Fate of Outbound Flight
Tatooine, Geonosis and the Arkanis Sector
Attack of the Clones
The Clone Wars (2 maps)
Kashyyyk and Neighbors
Revenge of the Sith
Imperial Atrocities
The Adventures of Han Solo 14-0 BBY
The Centrality
The Corporate Sector
Missions Merciful and Otherwise 2-0 BBY
The Ultimate Power in the Universe 22 BBY-12 ABY
A New Hope
Yavin and the Gordian Reach
Famous Shadowports
Flashpoints in the Galactic Civil War 2 BBY-4 ABY
The Road to Kessel
The Spice Trade
Hoth and the Greater Javin
The Empire Strikes Back
Endor and the Moddell Sector
Inner Zuma Region (Side View)
Return of the Jedi
The Ssi-Ruuk and Nagai Invasions
The New Republic Advances 4-6 ABY
The Road to Coruscant 6-7 ABY
The Hunt for Zsinj 7-8 ABY
Campaigns After Zsinj's Death 8 ABY
Thrawn's Campaigns 9 ABY