[Three personages in one old book]

It is always of interest, especially for medical practitioners, to learn about the lives of prominent scientists and their contributions to medicine. Briefly, we present here the highlights of three of those persons: Hermann von Helmholtz, one of the greatest minds in physics, physiology, optics, neurology, and developer of the ophthalmoscope, etc., along with two Mexican physicians, Manuel Carmona y Valle, prominent 19th century physician who was named "father" of ophthalmology in Mexico and Rafael Silva y Zayas, one of the brightest ophthalmologists of the first half of the 20th century in our country, eventually brought together, in communion, in one old book.