The book presents a new approach for efficient gridding and segmantation of microarray images. The Stationary Wavelet Transform is used for preprocessing of microarray images followed by Thresholding methods for segmentation. The global and local thresholding techniques are combined to improve the accuracy of segmentation and the log intensity ratio. The microarray images are taken from Standford Microarray Database. The proposed approach is reliable means for estimating gene expression than existing methods.