The book, "Paterno" by Joe Posnanski, was purchased Friday by The Associated Press in advance of its release next week.
In the book, Posnanski describes a scene at Paterno's home, two days after Sandusky had been charged with child sex abuse last November. Paterno's family and a close adviser were trying to explain to the Penn State coach that there was a growing sentiment Paterno must have known for years about the accusations against Sandusky.
The book quotes Paterno as shouting "I'm not omniscient!"
Paterno did not want to read the report, but family members and Penn State football communications and marketing assistant Guido D'Elia insisted that he must.
The book also indicates Paterno didn't comprehend all the terms in the report, asking his son what sodomy meant.
According to the book, later that night Paterno's son, Scott, told his mother that she should brace herself for the possibility that Joe could be fired.
Sue Paterno responded, "Scotty, that will kill him."
Paterno was fired by school trustees two days later, on Nov. 9. He died in January at age 85 of cancer.
Sandusky, Paterno's longtime defensive coordinator, is jailed and awaiting sentencing after being convicted in June on 45 criminal counts involving 10 boys.
Former Athletic director Tim Curley and now-retired school administrator Gary Schultz are awaiting trial on charges of lying to a grand jury and failing to report the abuse allegations against Sandusky.
Paterno was not charged, though the NCAA last month slammed his beloved football program with a range of tough sanctions. Among them, the Nittany Lions were forced to vacate 112 wins from 1998-2011, meaning Paterno no longer has the most coaching victories in major college football.
The penalty seemed to grow from a report commissioned by the school from former FBI director Louis Freeh. It said Paterno, Curley, Schultz and former school president Graham Spanier concealed allegations against Sandusky dating back to 1998. Paterno's family and the three officials have all vehemently denied the conclusions.
Paterno had granted access to Posnanski to write a biography in 2011, well before Sandusky was charged.
"Nobody would argue and certainly my book does not argue that the good Joe Paterno did in his life should shield him from the horrors of his mistakes," Posnanski wrote in a column for USA Today earlier this week. "Some would argue, especially in the white-hot emotion sparked by the latest revelations, that Paterno's role in the Jerry Sandusky crimes invalidates whatever good he might have done. My book does not argue that either. My book, I believe, lets the reader make up his or her own mind."
The book also details the long and frosty relationship Paterno had with Sandusky while they worked together at Penn State.
According to the book, the two were never friendly and late in Sandusky's tenure, Paterno felt the defense was not performing well and neither was Sandusky.
Paterno did not want to fire Sandusky because he was so popular in the community and with fans, according to the book. The book indicates that Sandusky showed interest in taking an early retirement in 1999, and Paterno encouraged him to do so and let his assistant know he would not be the next head coach at Penn State.
Sandusky and Curley negotiated a retirement package, and among Sandusky's demands was to stay on through the 1999 season.
The book indicates Paterno reluctantly agreed, and then regretted the decision when the team, which was considered one of the national championship favorites going into the season and reached No. 2 in the nation, lost three games late in the year with an underperforming defense.
Sandusky's early retirement at age 55 has led to speculation that a 1998 allegation by a boy against Sandusky that was never prosecuted by authorities led to Penn State quietly pushing Sandusky out.
Paterno told a grand jury he was unaware of that allegation but evidence uncovered by Freeh report investigators suggest that he did.
According to the book, Paterno, who obsessively took and kept handwritten notes, had no notes in his files that mentioned the investigation.