Michael H. Gerardi holds an M.S. in Biology from James Madison University and has served as an expert witness for the US EPA on nitrification and denitrification. In addition to the prior books in Wiley's Wastewater Microbiology series, he has authored more than one hundred technical publications and has provided wastewater microscopy and consulting services for numerous municipal and industrial wastewater treatment plants. He is currently an operations specialist for Cromaglass Corporation in Williamsport, Pennsylvania. Brittany Lytle is a native of central Pennsylvania and graduate of Lycoming College. She has illustrated two books, numerous poems, Pennsylvania State University course manuals, and had many solo and group exhibitions in the Williamsport, Pennsylvania area.