Antique lap desks had hinged writing surfaces, often covered in leather, felt, or other material, that flip up to reveal storage space for papers.
Individual compartments were designed to hold inkwells, pens, sealing wax, and other contemporary writing materials.
There are a wide variety of forms available, but as a rule it is much smaller and simpler than the antique lap desk, having at the most a small drawer or holding area for a ballpoint pen and a pencil.
Finally, some come with a built-in battery powered lamp, continuing the tradition of those antique lap desks and writing slopes which had swinging or hinged brass candle holders built in.
Most modern lap desks are considered specialty items and very few furniture dealers keep them in stock.