Mr. RADical's journal is a holodisk in Fallout: New Vegas.
Location
It can be found on the body of Mr. RADical (scavenger in-game) located southeast of Novac.
Transcript
Day 1: Love the suit. Can scavenge anywhere now, screw the rads. I hereby christen myself Mr. RADical. Get it? Ha!
Day 4: Suit passed first test with flying (yellow) colors. Overnight visit to Yucca Mountain. Didn't go too deep because something big moving down tunnel. Rad level high even where I was, and I didn't feel a tickle. Go, rad suit, go!
Day 5: Vomited all morning. Didn't splash on suit or I'd be pissed. Must be something I ate.
Day 9: Exciting! Ran across old woman's scrap yard. Bought glowing container for measly 50 caps. Heading for Clark Field to prove suit at higher rad levels. If it holds up, I'm going to pop this jar of goop open and pour it all over me! I bet I could swim in this stuff if I had enough of it! Oh yeah!
Notes
According to the holodisk, the owner of the suit thought it would fully protect him from radiation. As described in day four, the radiation level was high where he traveled. The next day he became sick, which is obviously radiation sickness due to his exposures. The last day, nine, he had gone to prove that the radiation suit was extremely resistant to radiation. He was proven wrong.
