From the back cover:

To those interested in a life in science, Sir Peter Medawar, Nobel laureate, speaks with warmth and pride of his calling. He deflates the myths surrounding scientists -- invincibility, superiority, genius; instead, he argues that it is common sense and an inquiring mind that are essential to the makeup of a scientist.

This book, published in 1979, was the second in the Alfred P. Sloan Foundation Series; Amazon has ten sample pages available for your review. The first book in the series was _Disturbing the Universe_, by Freeman Dyson.