RM - Publishers set specific print runs for a book based on their Profit and loss, or P&L, statements. That spreadsheet shows what format the book is in, what they need to charge, and how many copies they have to sell against the author's advance in order to show a profit.
When a book goes back for a second or third printing, it means they have run out of copies but still believe they have significant demands (usually through re-orders from bookstores) in order to print more. Same for a third, fourth, fifth printing, etc.
Initial print runs can be intentionally lower than demand, in order to make it seem the book is doing well by going back for more printings or they can be legitimate - the book sold well beyond expectations.
Hope that helps!
-Joe
When a book goes back for a second or third printing, it means they have run out of copies but still believe they have significant demands (usually through re-orders from bookstores) in order to print more. Same for a third, fourth, fifth printing, etc.
Initial print runs can be intentionally lower than demand, in order to make it seem the book is doing well by going back for more printings or they can be legitimate - the book sold well beyond expectations.
Hope that helps!
-Joe