I started playing Batman: Arkham Asylum yesterday and I found it amazing. I played it for a couple hours until I arrived in Arkham North, but then my left eye started hurting like crazy and I had to rest for a while.
Today I progressed a little more and came into Arkham Mansion. My mission was to reach Dr. Young’s research notes before Joker did. I had to get in her office to get the notes and even though I was able to pinpoint its location, I couldn’t get in. It took me a while to find where to go, but I did it. Here’s how to enter the office.

Warning! This post may contain spoilers.

There are two entrances to the office, one through a blocked door in the North Corridor, and another through an electric fence which I couldn’t get through at that moment.

Location of the office

Northern entrance to the office

You should see a vent to the left of the door.

The vent to the left of the blocked door

When you go through it, you’ll end up in a room where there is a barred section to the left. If you look at that section closely, you’ll see that the walls have writings on them. If you haven’t solved the riddle in this part (North Corridor – “Did Amadeus go mad, or was he just dizzy?”), face your character directly at them and hold X (or whatever your detective mode key is) to solve it.

North Corridor riddle – “Did Amadeus go mad, or was he just dizzy?”

Exit the barred section and you should see another vent up on the wall to your left. I took the screenshot this way so it shows both the entrance to the barred section and the vent access to the office.

The other vent

Well it’s pretty linear afterwards, and I don’t want to spoil more, so my post ends here. Hope it helps!