So many, in fact, that since the late nineties, half a million dollars is de rigueur for a first novelist whos perceived to have hot prospects.  And the recession that has caused sales of all but a few books to flat-line hasnt slowed the run on mega-advances; if anything, the desperation to find the next Alice Sebold has only upped the ante.  In the past two years, a steady stream of first-time authors have joined the club. 