Thrifty Decor Chick DIY built in library bookcases
Black hardware with white shaker cabinets. Love the shaker style doors; note the middle "third" is larger than the two side panels; think squares.
Custom Bookcases NY Built-in Bookshelves Fine Cabinetry — Hudson Cabinetry Design
How to easily DIY built-in bookcases from IKEA Billy book shelves, and easy IKEA hack you can do in a weekend. - My Wood Den
window seat in home office between built-in bookcases *Wood trim continuous from wall to bookshelves!
How to Build a Built-in Bookcase | The Family Handyman