AUSTIN - Gov. Rick Perry's heavy use of painkillers to help relieve severe back pain may have kept the governor from the top of his game last fall during an aborted presidential run, according an e-book being released Tuesday.

Perry campaign adviser Ray Sullivan swiftly denounced the book Monday as "irresponsible, unsourced and unfounded 'reporting.' "

"Inside the Circus," a book about the Republican presidential race by veteran journalists Mike Allen and Evan Thomas, describes a bizarre men's room scene where a campaign manager for a rival overhead Perry belting out, "I've Been Working on the Railroad."

Read more here at The Houston Chronicle.