Atomic Physics for Everyone (2025 open access book)

The subtitle of the book is;

An Introduction to Atomic Physics, Quantum Mechanics, and Precision Spectroscopy with No College-Level Prerequisites.

As such it is accessible from high-school to beginning-undergraduate students. It is also a pretty recent (2025) book and hence the Physics is quite upto date.

Since Atomic Physics is Modern Physics, its importance cannot be understated. Much of modern civilization is based on technology constructed through precise engineering based on these concepts. Hence a sound understanding of its basic concepts is mandatory for every educated person today.

PS: You can get a lot of free open access books on various subjects at Open Textbook Library - https://open.umn.edu/opentextbooks and Open Educational Resources - https://oercommons.org/hubs/open-textbooks