We are pleased to publish the third issue (Vol. 2, No. 1) of Journal of Innovative Optical Health Sciences (JIOHS) which focuses on the developments and biomedical applications of nonlinear optical (NLO) microscopy. NLO microscopy is becoming a powerful tool for bioimaging due to several unique advantages over traditional methods. Nonlinear dependence on excitation intensity gives NLO microscopy inherent three-dimensional (3D) imaging capability without the need for a confocal pinhole. This is particularly advantageous in the case of tissue imaging where significant scattering can reduce the signal collection efficiency by confocal detection. Laser scanning facilitates real-time NLO imaging of live tissues and animals. NLO microscopy utilizes near IR excitation which provides both superior optical penetration into tissues as well as reduced photodamage due to reduced interaction with endogenous molecules. This issue includes seven original papers and five review articles.