Every year are published around a dozen of books directly related to my research. By directly I mean on the same topics of my research, normally by authors I am familiar with, and potential reference sources for my current or future research. Some are fairly technical, but others can be of more general interest, or, for example, more on the policy side. I think it is not that controversial that one uses "normal working hours" (e.g. whilst in the office) to read these books.

However, my problem is with books that are not directly related to my research, but which pertain to topics that might be indirectly related to it, or which I think might be interesting to explore in order to foster interdisciplinary work, or which are of another sub-discipline I don't research on, or books that refer to academia and science in general, or to teaching. Naturally, there are hundreds of these books published every year, and I do not aim to read them all. But some are of particular interest to me.

Is it socially accepted for one to use "working hours" to read these books? Or are these expected to be read only outside work, e.g. on weekends, or holidays, or so? What's your experience on this?