The books were seized by Los Angeles police during a molestation investigation involving a boy who received a multimillion-dollar settlement from Jackson in 1994. That probe never led to criminal charges against Jackson.
Judge Rodney S. Melville allowed the prosecution to use the books despite defense objections that they were found too long ago to be relevant to the current case and would be prejudicial.
"If these are truly pornographic books, these books will push every emotional button of the jury," said legal expert and courtroom observer Michael Cardoza.
CBS News Correspondent Jennifer Donelan reports the books could speak directly to the child molestation case against Jackson. But as prosecutors prepare to wrap up their case, legal experts warned the their conspiracy case against the King of pop has been seriously damaged.
"They need to bring in one believable witness to tie Michael Jackson to the conspiracy in this case," said Cardoza.
Jackson is accused of molesting a 13-year-old boy in 2003, giving him alcohol and conspiring to hold the accuser's family captive to get them to rebut a documentary in which Jackson appeared with the boy and said he allowed children to sleep in his bed but that it was non-sexual.
Jurors were shown the covers of the two books during questioning of Los Angeles police Detective Rosibel Smith, who found the books in a locked filing cabinet in Jackson's master bedroom.
One book, called "Boys Will Be Boys," featured an image of fair-haired boys in swimsuits jumping into water.
The book contained an inscription written by Jackson: "Look at the true spirit of happiness and joy in these boys' faces, this is the spirit of boyhood, a life I've never had and will always dream of. This is the life I want for my children."
The jury also was shown the cover of a book called "The Boy: A Photographic Essay." It also contained an inscription that said: "To Michael from your (heart symbol) fan, XXXOOO, 'Rhonda."' The note was dated 1983.
Smith said both books featured boys "playing, swimming, jumping."
Prosecutor Ron Zonen said earlier that one book was about 90 percent pictures of nude boys and the other about 10 percent.
Prosecutors have previously introduced dozens of adult magazines featuring adult women as well as a few art books that featured nudes.