The more time goes by, the more I value what I learned from Peopleware (DeMarco, Lister) 20 or so years ago. It seems so clear, precise and uncluttered compared to modern efforts.
Peopleware is a classic. It's genius lies in the fact that it's able to shine a light on the important aspects of productivity and work life that fall between the cracks in our quest to 'measure' productivity and be 'efficient' (Taylorism).
The big issue it has, IMO, (which other DeMarco books like 'Slack' share) is that it does not provide actual case studies that would convince a typical executive / manager working in a high pressure / competitive environment to change their methods.