BRASILIA (Reuters) - Brazil will offer inmates in its crowded federal penitentiary system a novel way to shorten their sentences: four days less for every book they read.

Inmates in four federal prisons holding some of Brazil's most notorious criminals will be able to read up to 12 works of literature, philosophy, science or classics to trim a maximum 48 days off their sentence each year, the government announced.

Prisoners will have up to four weeks to read each book and write an essay which must "make correct use of paragraphs, be free of corrections, use margins and legible joined-up writing," said the notice published on Monday in the official gazette.

A special panel will decide which inmates are eligible to participate in the program dubbed "Redemption through Reading".

"A person can leave prison more enlightened and with a enlarged vision of the world," said Sao Paulo lawyer Andre Kehdi, who heads a book donation project for prisons.

"Without doubt they will leave a better person," he said.

(Reporting by Peter Murphy; Editing by Anthony Boadle)