I would like to share that I have written a book about OpenStreetMap and related open-source projects, which has just been released.
The book provides an overview of the OpenStreetMap ecosystem and companion tools such as Overpass, Nominatim, Leaflet, and Folium.
It then explains, through practical examples, how to use these tools to build interactive maps in web applications.
The approach is progressive: it starts with simple use cases using one tool at a time, and then moves on to more advanced scenarios combining multiple tools.
I hope it may be useful for developers or contributors who would like to deepen their understanding of the OSM environment.
More information is available here: