A vaccination failure occurs when the chickens do not develop suitable antibody titer levels and/or are susceptible to a field disease outbreak. Therefore, an updated review (visual-type) has been thoroughly developed in order to highlight the importance of detecting and solving the major vaccination failures in commercial chickens to control diseases affecting this species. The handbook has been written by a prestigious expert with a wide experience in this field. Numerous graphic resources have been included to complement the information provided and make the contents more understandable and accessible to readers.