The Lineages and Histories of the Great Houses of the Seven Kingdoms

"I hear you're reading a boring book."

- Petyr Baelish to Eddard Stark

The Lineages and Histories of the Great Houses of the Seven Kingdoms is a book detailing the history of the Great Houses of the Seven Kingdoms, including the lineage and appearance of all heirs, with illustrations of each house's individual sigil.

The tome lists the lineages of houses both Great and Noble. Among them are House Baratheon, House Umber and House Blackfyre.

Season 1
Lord Jon Arryn asked Grand Maester Pycelle for the book shortly before his death. When hearing of his old mentor's interest in the tome, Eddard Stark borrows it from Pycelle as well.

After his daughters note that Joffrey Baratheon has blond hair, Lord Stark checks the Lineage and Histories, and discovers that all members of House Baratheon are described as "black of hair", except for the "golden headed" Joffrey, leading Ned to realize that Joffrey is not Robert's child, and thus not the real heir.

In the books
In the A Song of Ice and Fire novels, The Lineages and Histories of the Great Houses of the Seven Kingdoms, With Descriptions of Many High Lords and Noble Ladies and Their Children is an old book written by Maester Malleon. It doesn't mention the current Baratheons or Lannisters, but it mentions that throughout written history all Baratheons have been black-haired and that, likewise, every recorded union between Baratheon and Lannister has produced black-haired children.