elena does her homework and decides to sell the strad through chris reuning from reuning & son. chris is a rare-instrument dealer. he's also a cellist and a luthier, someone who makes or repairs stringed instruments. how do you decide what bernard's stradivarius is worth? >> well, i think the first thing, you have to evaluate the quality. and then it also helps to know what the market history has been. so, in the case of this cello, we did know what other stradivari cellos had sold for. and we could compare the quality of this one to those. >> back in 2002, a similar cello sold for $5 million. but over the past several years, collectors have driven the price of rare instruments way up, and each one has its own history -- a unique story that's a big factor in whether it fetches a 6-, 7-, or even 8-figure price at auction. nobody knows this cello's story better than elena's husband, nicholas delbanco. a novelist by trade, delbanco actually wrote an entire book about the instrument. it's called "the countess of stanlein restored," and it describes the painstaking restoration his fat