The strength of the book is the delicate balance of theory and instrumentation and applications. For example, the chapter on the design and construction of a confocal microscope that corrects for aberrations will appeal to all of us who design and construct optical imaging instruments. The author begins by stating a series of critical design questions. Once the author formulates the answers to the basic design questions he proceeds to design and construct the instrument. This is a useful and a logical approach to instrument design and development that is often not discussed in publications and books. The author first determines the sources of the optical aberration; which have their origin in the optical system and which are from the specimen. Then the magnitudes of these aberrations are estimated and a design decision is made of which aberrations are important and which can be ignored. The critical author also compared the Zernike coefficients, as measured mean and standard deviations, for several different biological specimens: the mouse oocyte cell, the mouse blastocyst, and the nematode C. elegans. Finally the author evaluates the effect of the numerical aperture on the aberrations. The critical discussion of which level of aberrations correction makes sense highlights the thinking of the instrument designer and builder. The lesson that is apparent to the reader is that the optical aberrations in a microscope depend on several factors: the instrument, the specimen, and the numerical aperture of the objective. Therefore, statements about the efficacy of adaptive optics to correct aberration must specify these parameters and meaningful comparisons are only valid between similar systems, objectives, and specimens.