are there any books about secular spirituality?

not sure if this is an odd question. i love many aspects of dif spiritualities. but i am also fairly skeptical and not someone who leans towards faith just for the sake of it, but rather gravitate to what can be proven. are there any books that have to do with like…secular spirituality? is that a thing? stuff not to do with supernatural aspects or dieties, but things that are somewhat science backed and are more related to mindfulness, connection to nature- connection in general.