NO PRE-DRILLED HOLES! The description does not list any tools like a drill needed for this. Luckily my partner and I are pretty active so he was able to use enough force to screw threw the shelf pieces while I tried to hold it in the correct spot. The overall outcome leaves shelves that are not perfectly aligned/flush. We also had our own heavy duty screwdriver, if we only had the one provided we wouldn't have been able to put this together. Not looking at things too closely it looks good but wish we knew what we were getting into prior.