HOW Long 'til the next book?!?

I have, as you might suppose, been getting a certain amount of agitated mail following publication of ECHO, [g:] all centering on one question: HOW long is it until the next book will be out?!? (This accompanied by various pleas of increasing age or senility on the part of some readers. It's not that I'm not sympathetic, and I _am_ flattered--but the fact that you think you might not live long enough to read the next book really can't make me write any faster. Look, just exercise and take ...