Andrew Kessler

For authors, one of the risks of doing promotional events is sitting at a table stacked high with books and reading to an empty room. Even in this era of social media, getting out into the meatspace to build an audience is vital for authors. But not only is it demoralizing when the book you've poured your passion into is met with a shrug (or worse), it's a big waste of time—time that could have been spent, say, promoting a more successful event.

What's an author to do? Andrew Kessler—entrepreneur and author of "Martian Summer," his first-hand account of shadowing NASA's 2009 Phoenix Mars Lander mission—thinks he has an answer.

It has never been clear whether author book tours are a worthwhile investment. Fewer publishers are shelling out to send their authors across the country these days and BookTour.com shut down last year, conceding that “fewer author tours and changes in book marketing budgets have made our company financially unviable.” Now Brooklyn-based startup Togather hopes to make author book tours more of a sure thing by adding a group-buying dynamic that requires people to commit and buy a book before an author event takes place.