I've searched the web for bat house plans and information, and found the information to be very spotty and inconsistent. This book reflects the results of Bat Conservation International's "North American Bat House Research Project", which has been collecting data on thousands of bat houses for over 10 years. The book has detailed plans for a small economy house, a large economy house, and a nursery house, plus LOTS of information on bat preferences and ideas for experimentation. I built the nursery-style bat house, and it was occupied last year.