Here is a good article https://homeguides.sfgate.com/refinish-antique-wood-table-inlays-105794.html
To sand indoors, use a hand sander, not an electric sander. Wipe the wood with a damp cloth, sand on or over a damp cloth, and clean up frequently with a small vacuum cleaner. Rinse the sawdust out of the damp cloths regularly. This should keep further cleanup to a minimum. Even in the garage or workshop, don’t let sawdust pile up. It can become a fire hazard. Jewell
I would use a palm sander. All the inlaid pieces should be the same thickness. And if they are not, the palm sander will take care of that. Keep cleaning the wood dust up and wear safety glasses, mask, and gloves. Depending on the size of your bookcase, this may turn into a labor of love.