Lyndon B. Johnson

The lower spreads mean lower costs for investors, because Nasdaq investors generally do not trade directly with one another. Instead, they usually buy and sell from market-makers, brokerage firms that flip shares between buyers and sellers and keep the spread for themselves.

The historical novelist has to consider what has actually happened, while the SF writer is dealing in possibilities, but they are both in the business of imagining a world unlike our own and yet connected to it.