$50k novel advance == "almost qualify for foodstamps"

"If I published only one book a year, and it did as well as this one, my net would be only around $2500.00 over the income level considered to be the US poverty threshhold," writes a bestselling author. The math: $50k advance, half of it lost to agent and other costs, and even bestseller royalties don't immediately cover the advance to create a return. But ... what if one wrote two books in a year?