By Gaston Bachelard.
This is a philosophical piece on the processes of scientific reasoning and development. The writing is smooth and despite the sometimes “scientific” subjects, it is easy to follow for most of the time. An enjoyable read that I highly recommend if you can pick it up on the cheap and you are interested in the philosophy of science.
Most of the chapters require some knowledge in physics, ranging from basic stuff to more advanced concepts. The more advanced chapters are a bit difficult to follow if one only has the basics down (like me), but with a little effort the contents can be digested in a timely manner.
All in all, if you have some basic understanding in physics, are willing to do a tad bit of research on the side (to receive the full effect of the writing) and want to read on the philosophy of science, this is a nice addition to your library.