How can I attach 2 Billy bookcases?

Sorry, don't know about Billy bookcases. Never heard of them.

https://www.bing.com/videos/search?q=How+can+I+attach+2+Billy+bookcases+to+make+a+dressing+room&qpvt=How+can+I+attach+2+Billy+bookcases+to+make+a+dressing+room&FORM=VDRE

https://abeautifulmess.com/2018/06/built-in-ikea-billy-bookcase-hack.html

https://www.pinterest.com/pin/727401777284029109/?lp=true

https://www.ikeahackers.net/2014/07/how-to-make-a-billy-bookcase-look-expensive.html

https://lifeonsouthpointedrive.com/diy-built-ins-ikea-billy-bookcases/

https://addicted2diy.com/billy-bookcase-ikea-hack-update-a-simple-bookcase-into-a-custom-built-in-part-1/

Not sure I completely understand your intended set up? Love Ikea Billy bookcases, very versatile and lots of hacks for them.

Maybe I wasn't very clear Naomie. Here in France you can buy pre-made dressing wardrobe units but they are very expensive and they are only 17 to 18 inches deep. I want those units about 22 inch deep : a folded t-shirt is 8 inches wide (I could put 2 rows of them in for example long-sleeved ones in the back because it's summer).

All the rest I want to put in there, other than clothes, is wider than 17 inches : suitcases on top of the units (23 inch) sewing machine (20 inch) winterduvets, boxes with Christmas decoration..without sticking too far out in that little dressing area. I have to do with an area of 55 inch by 110 inch.

Now, those Ikea Billy bookcases. They are very cheap. I was planning to assemble half of them with the carton backing, the other half without the backing and put one in front of the other. Attach them to each other, but I don't know how. Maybe just glue?

Hi, I came across this while looking up if anyone has done this. I, too, am wondering If this is possible and would be stable enough ug to hold some expensive statues. Did you ever end up doing this? If so, how did it turn out?

Can you please post a picture of your completed wardrobe project? It's difficult to visualize.

What did you do with the gap between the shelves? I am trying to do what you did but for my hall closet.