The "Game Of Thrones Wiki" concerns itself with the TV series only, which is why I draw information from that, rather than from "The Wiki Of Ice And Fire". I don't want the show spoiled for my readers who - like me - have not yet read the books.
However, this entry for Tywin Lannister seems to have more details than have yet been revealed in the series. But after reading it through, I don't really see anything that ruins the experience for the viewer. It appears to be mostly background material that would only be told in some future episode, not shown.....
LORD TYWIN LANNISTER
George R.R. Martin
AS SEEN IN:
'Game Of Thrones'
The battlefields, Harrenhahl, Westeros, Mondas
From the "Game Of Thrones Wiki":
Tywin Lannister is a major character in 'Game of Thrones'. He is played by guest star Charles Dance and débuts in the seventh episode of the first season. Tywin Lannister is the head of House Lannister and the lord paramount of the Westerlands. He is rich, powerful and entitled. His primary concern is with the legacy of his house.
Tywin is the head of House Lannister, one of the Great Houses and among the richest and most influential families in Westeros. He is a widower with three children, Jaime, Cersei and Tyrion. He is the Lord of Casterly Rock, Warden of the West and the lord paramount of the Westerlands.
Tywin is the son of Tytos Lannister. His father Tytos Lannister presided over a period of decline for the house. He frittered away much of their fortune on poor investments and allowed himself to be mocked at court creating a perception of weakness. Their vassals House Reyne of Castamere rebelled against Lord Tytos. Tywin put down the rebellion personally, extinguishing their house and re-establishing the fearsome reputation of House Lannister. His ruthlessness gave darker meaning to the common phrase "A Lannister always pays his debts" and was immortalized in the song "The Rains of Castermere".
Tywin despises and hates his younger son, seeing him as misshapen and perverse. When Tyrion was very young, Jaime set him up with a prostitute. Jaime posed her as a common girl in distress that they rescued from bandits. Jaime chased the bandits off while Tyrion comforted the girl. They married, but when Tywin found out he was furious and got Jaime to reveal the truth. Tywin paid her for everyone of his guards to have sex with her and forced Tyrion to watch. Tywin's hatred of Tyrion has been reciprocated since.