I highly recommend Alister McGrath's textbook Christian Spirituality: An Introduction that covers the theory and the practices of all major denominations, making it a kind of guide book before you choose one theory+practices and "go deep". What's sometimes called "mysticism" is included in that textbook. The book has extensive bibliography to help you choose a book that guides you in a particular theory.

Each of all Christian spiritual practices presumes a theory which in turn is based on the theology of that branch / denomination. So when choosing, first choose the theology, then the theory, then try the practices. If it doesn't work for you, choose another theory, or even another theology, and try to corresponding practices. As long as the theology stays within the orthodox 3 main branches, you're okay.

I highly recommend Alister McGrath's textbook Christian Spirituality: An Introduction that covers the theory and the practices of all major denominations, making it a kind of guide book before you choose one theory+practices and "go deep". What's sometimes called "mysticism" is included in that textbook. The book has extensive bibliography to help you choose a book that guides you in a particular theory.

Each of all Christian spiritual practices presumes a theory which in turn is based on the theology of that branch / denomination. So when choosing, first choose the theology, then the theory, then try the practices. If it doesn't work for you, choose another theory, or even another theology, and try to corresponding practices. As long as the theology stays within the orthodox 3 main branches, you're okay.

A more famous practice usually has a few key figures and a large following in history. Therefore, additional safeguard is to evaluate the reputation of the key figures, the fruits of the majority of the followers (whether they exhibit Christlikeness), how long the practice has been around (time tested is always better), and how widely practiced it is across cultures (more universal is better). If the practitioners span multiple denominations it's even better!

I highly recommend Alister McGrath's textbook Christian Spirituality: An Introduction that covers the theory and the practices of all major denominations, making it a kind of guide book before you choose one theory+practices and "go deep".

I highly recommend Alister McGrath's textbook Christian Spirituality: An Introduction that covers the theory and the practices of all major denominations, making it a kind of guide book before you choose one theory+practices and "go deep". What's sometimes called "mysticism" is included in that textbook. The book has extensive bibliography to help you choose a book that guides you in a particular theory.

Each of all Christian spiritual practices presumes a theory which in turn is based on the theology of that branch / denomination. So when choosing, first choose the theology, then the theory, then try the practices. If it doesn't work for you, choose another theory, or even another theology, and try to corresponding practices. As long as the theology stays within the orthodox 3 main branches, you're okay.