Adaptive optics in biology Biological imaging at the cellular level particularly in vivo is a key enabling tool for understanding biological processes disease diagnosis and drug development. Unfortunately specimens under observation often introduce optical aberrations that degrade the imaging resolution particularly when imaging deep into tissue. Adaptive optics counteracts these effects. This technology originally developed and applied in astronomy has been increasingly applied to ophthalmics and microscopy. This book introduces the key concepts and technologies behind adaptive optics. The wide diversity of imaging methods used in biological imaging requires multiple approaches to adaptive optics. Methods fall into two broad categories those that use a direct measurement of the aberration and those that do not. Relative advantages of each are described. Application results are presented. Finally current technology trends and promising future application areas are discussed.