In the study I did not put up any walls, the whole floor is one big room.
I have shown before how I made the book case. Most of the books I now added are pieces of cardboard glued together and bound in cloth or leather. There are magic signs on the bindings because they are books of magic. The globe is a pencil sharpener from ebay. The walking stick on the right is made from a makeup-brush handle with a fancy plastic bead on top, painted gold. The cello is a fridge magnet, generously donated by a grandchild. The window is made exactly the same manner as the white one. The floor is self-adhesive shelf paper.
I made another, low chest of drawers to put ornaments on. I made the armchair and stool using a pattern from a book. Both are made from cardboard covered with fabric. The legs are IKEA furniture pegs. I bought the fabric from ebay because I didn't have anything suitable. On ebay you can get small bits of fabric people use for patchwork. On the chest there is a pair of candlesticks that I made with plastic tubes and buttons. And here are some more details from the study