This is a great book to get started - and whilst it is a little dated technology wise the fundamentals are great along with a very entertaining tongue-in-cheek presentation/writing style.

https://www.amazon.com/How-DJ-Properly-Science-Playing/dp/05...

> Before digitisation, mixing records in a nightclub was a technical discipline as difficult to master as learning chord progressions on a guitar.

This is not true. Learning to beatmatch vinyl or with CDJs is mainly a matter of rewiring your brain to hear sound from each ear separately, and a little bit of muscle memory. You can learn it with about a month of daily practice.

DJing has always been about selection, and crowd reading.

EDIT: if you're interested, everything you need to know about DJing is in this book: https://www.amazon.co.uk/How-DJ-Properly-Science-Playing/dp/...