Isn't an easy puzzle...
WhyTheCombOfNatashaOtomoskiHas21Teeth?.txt
NatashaOtomoski > Satoshi Nakamoto...
21 > Total bitcoin supply in millions
.txt > Satoshi White paper?
Teeth >

I think the answer of this puzzle is in the bitcoin white paper... i will try to brute force that.
brute forcing is not good way for solving this puzzle. assume the white paper has 100 distinct words, total number of combinations is: 100! / (100-8)! = 7.50306389818e+15 . assume you have a good computer and it can compute 1000 combinations per second, total time of computing will be: 7.50306389818e+12 seconds= 237920 years.