Principles: Principles of Wave Optics. Principles of Geometric Optics. Theory of Image Formation. Methods: Aberrations and Benefit of Their Correction in Confocal Microscopy. Specimen-Induced Geometrical Distortions. Simulation of Aberrations. Overview of Adaptive Optics in Biological Imaging. Wavefront Correctors. Adaptive Optics System Alignment and Assembly. Applications: Indirect Wavefront Sensing: Sensorless Adaptive Optics for Microscopy. Implementation of Adaptive Optics in Nonlinear Microscopy for Biological Samples Using Optimization Algorithms. AO Two-Photon Fluorescence Microscopy Using Stochastic Parallel Descent Algorithm with Zernike Polynomial Basis. Pupil-Segmentation-Based Adaptive Optics for Microscopy. Applications: Direct Wavefront Sensing: Coherence-Gated Wavefront Sensing. Adaptive Optics in Wide-Field Microscopy. Biological Imaging and Adaptive Optics in Microscopy. Adaptive Optical Microscopy Using Direct Wavefront Measurements. Index.