Reach the Baron's private study | Chapter 6: A Man Apart Thief Guide

Before you go about the main objective, i.e. reaching Baron Northcrest's study, you need to make sure, again, that you have explored the entire villa in detail (the cellars, the ground floor, the first floor, the attic and the secret chamber), because this will be impossible to do, later on. Reach the waiting hall [Northcrest Manor - Waiting Hall] located in the Southern part of the building. At the first floor of the location, there is a the door shown in the above screenshot, which should be unattended by anyone.

You need to let go and land on a small balcony

Open the door [Northcrest Manor - Study Tower], turn right and reach the hole in the wall, under the ceiling. Jump down here, to a ledge below, and start climbing. This should not surprise you with any new elements. At the very end, jump down to a small balcony and jump into the tower's main part.

Use the claw to start climbing again

Here, you need to start climbing again, first by using the claw to reach the interactive ledge, located above the inactive elevator. Towards the end of your climbing, the elevator will be set into motion but, you do not need to do anything about it. Wait for the elevator to stop and finish climbing, which will take you to the upper part of the tower. Find a book (Baron Northcrest - Deathbed Confessions) here, and only after the new document has been added to your journal climb up the stairs, Open the door to the study, thanks to which the game will start a cutscene of the meeting with Baron Northcrest.