Behr Paint makes a interior stain stripper, there is some directions you will have to follow. It is in a spray can. your only other option would be to sand. so your options is a stinky stripper or a dusty house. I have used the stripper i sprayed it on let it sit 15 minutes and wiped it off. it worked , i still sanded a little.

It is called stain for a reason and you will not be able to remove all of it with a paint remover, but will only be able to get it a little lighter at best. You may be able to sand the stain out but it will difficult to get it out of all the nooks and cranies of the bookcase.
Good luck.

Sorry to say it but you will be sanding,stripper is made to take off products that dont penetrate,and seeing as that is all stain does.
It is soaked into the wood,where paint would be laying on top of the wood.
BUT....im not into using strippers to often so either way let us know if it worked.

the behr #500 is a stain stripper is made to penatrate and strip.
you spray on the stripper. Then scrub with a synthetic steel wool or nylon pad and then wash with water. you might have to do it a couple times. proper ventilation is a good thing because this product is methylene chloride.
If you cant find that product find a stripper with sodium hydroxide. it will penetrate then strip.

or just sand

Im going to have to try the behr 500 and give it a shot just so I can see how it works,im not big into strippers.
The hardest part to belive in a product that says it can strip stains is how does it lift the stain out of the wood.
I will get some at homedepot though and try on some sample boards just to satisfy my own curiosity and this way recommend it to others as well.

YOU HAVE EARNED MY RESPECT. MOST PEOPLE WOULD JUST BASH OR DOUBT. I WILL LOOK FORWARD TO HEARING THE RESULTS.

I JUST REALIZED THE # IS 599

Oh,ive done plenty of bashing around here,have you used this stripper personaly before?
I was a press operator and in 1 week with no experience I quit to start a painting business so my learning is from alot of researching asking questions (to a very reliable source) and the hardest and fastest way to learn the school of hard knocks.
Any problem or mistake that has been done im sure I personally have done it the 1st 2 years in business now many years later,I know my painting pretty good.

i HAVE USED IT AND IT DID DO A GOOD JOB I ALSO FOLLOWED THE DIRECTIONS, 99. PERCENT OF THE TIME NO MATTER WHAT PRODUCT USED IF THERES A PROBLEM ITS HUMAN ERROR .