I'm new to writing and, like most newbies I'm sure, am blindly feeling my way around the entire process. I was even naive enough to believe that writing the story would be the difficult part, when in fact that was the easiest part of all! As I began my story I realized that it could not be told in one book, therefore there are two books.
The first book is complete--edited and polished to the best of my ability and I'm ready to query. The second and final book is written, however, I still have about another 50 rewrites, some editing, and likely lots of polishing left on that one.
My question is this: should I wait and query the first book when the second one is ready? I read your blog as well as your QueryShark blog and know that you advise to query one manuscript at a time. If that is the case, should I at least mention the fact that there is a second book in my query for the first one?
Having something to work on while you query that first book is better than waiting to finish both books to start querying. Querying can take a while, what with those vast stretches of silence we seem so fond of inflicting on y'all. (38 people are suffering this at my hand as we speak.)
Whether to mention this is part of a two-book series depends on a lot of things. Can Book One stand alone? Does it wind up ALL the plot points or do some of the plot points remain unresolved so as to appear in Book Two? You don't want to convey the idea this is a standalone and make an agent think you don't know how to actually finish a book when s/he reads Book One and the fate of the Buttonweazer Clan is still unresolved on page The End.
You can do this by saying "I envision this as the start of a two-book series. I am finishing up the second book now."