There are many books, but in the end this can't be thought in a book. Bodhipath is probably a good place, they also have lots of online things to read: https://bodhipath.org/.

It's more focused on the compassion part. The mystical is something which is easy to find online, but hard to find someone with the experience.

But there are different schools, more focused on study, mediation etc. Some are more formal, others informal.

1) Words of My Perfect Teacher: A Complete Translation of a Classic Introduction to Tibetan Buddhism by Patrul Rinpoche translated by Padmakara Translation Group.

2) Essential Mind Training: Tibetan Wisdom for Daily Life translated by Thupten Jinpa.