In his 1930 book, Dirac took for granted that measurements could be made, but was very vague about what was actually involved.
Willis LambI liked quantum mechanics very much. The subject was hard to understand but easy to apply to a large number of interesting problems.
Willis LambA gifted experimentalist, and theoretician, in the best Newtonian tradition... His contributions to quantum measurements, and elucidative teachings on quantum mechanics, have not yet received the attention they deserve.
Willis Lamb