Let me offer an overview of principles that we can refer to as we try to understand what the Buddhist Path is about. This ‘system of practice’ was developed originally by my teacher Sangharakshita. It’s helpful for gauging our own spiritual experience and knowing how all the different methods and approaches fit in.
Buddhism has a rich tradition of meditation methods. Buddhaghosa (5th century CE) records the Buddha teaching forty, and thousands more were added as the tradition deepened and entered different Asian cultures. The variety of methods may come as a surprise; generally, mainstream Buddhist communities focus on just one or two techniques. This is because the Buddha taught three key areas of practice, some form of which all newcomers will start with.
Everyone needs to become 1) more integrated and concentrated, 2) more happy, empathic and loving and 3) more deeply aware. In my own tradition, the Triratna Order, we call these ‘integration’, ‘positive emotion’ (or skilful intention) and ‘mindfulness’. The first two involve directed effort – you cultivate concentration and develop your capacity to love. But in its pure form the third, mindfulness, is not about cultivating anything; it’s simply being aware of what is happening.
Thus 1) and 2) are active meditations – cultivated in a general way through anapanasati or mindfulness of breathing, and metta-bhavana or the development of goodwill – 3) is receptive. Note that the full, extended practice of mindfulness, as outlined in the Satipatthana sutta, does have an active developmental aspect. However the basic mindfulness practice is receptivity and openness to the actuality of all experience, and that is equivalent to the Just Sitting meditation.
So here emerge the main principles in our system of spiritual life. First comes the difference between those practices that actively cultivate particular qualities, and those that receptively ‘take in’ current experiences. Then there is an ordering, a sequence of regular steps: concentration, positive emotion and mindfulness are basics everyone needs to have established before attempting in any depth the more advanced stages of meditation, which are concerned with insight or wisdom. It’s not that that attempt shouldn’t ever be made, and it may well happen that we do experience levels of awareness or insight way beyond our current stage of realisation. However, inspiring and important though these may be for us, they are usually temporary. We have to drop back and continue putting down roots in the here and now:
First, you help your mind to become concentrated and unified, that is you develop integration. This makes it easier to develop, secondly, love, confidence and kindness: in other words, positive emotion. These two are the foundation for insight to arise. For most people, they are developed more or less simultaneously, and in some cases positive emotion may come first. 
Insight meditation is the other main area of practice. It involves reflecting on the nature of our existence and seeing the truth. The approach is very different, difficult to sustain until the work in the previous stages has established a positive, integrated state of mind known also as dhyana (jhāna, Pali).
Dhyana mind is fresh, open, clear and concentrated at a level that makes it possible to explore our experience in depth and see through the many veils of over literal assumptions and views. The beginning stages of dhyana are enough to do that effectively. Without it, though, our insight contemplations are likely to be unclear and unfocused; they will not result in any actual insight.
The realm of practice aimed at cultivating dhyana, equivalent to the stages of integration and positive emotion, is generally known as shamatha or ‘calming’ meditation. The realm of insight meditation is known as vipashyana, which means ‘seeing.’ (Pali: Vipassanā.)
Practised within a state of well established shamatha, vipashyana methods eventually produce results: we really do see through our views and assumptions. A moment of true seeing is radical and something of a shock; it can set off a process that culminates in the collapse of everything we previously took for granted. It is the most crucial transition of anyone’s spiritual life. We therefore call it the stage of spiritual death, which is not putting it too strongly; like death, real insight is always unexpected, always resisted, always life changing. ‘Death’ also suggests the possibility of a renaissance, a rebirth into a new kind of existence. Until our old ways finally die off, nothing new can come about.
The collapse of the old viewpoint makes it possible to abandon delusion and let go into the positive, maturing aspect of insight. Here you draw nearer the Buddha, entering the phase of insight meditation concerned not so much with breakthroughs and realisations but with the process of becoming fully awakened. The practitioner starts to be transformed in a permanent way by letting in the nature of reality. This phase of the system of meditation is termed spiritual rebirth. 
Each of the four cumulative stages is associated with methods that typically cultivate it, though with experience comes the ability to cultivate any phase with any practice. Most methods can be approached from either a shamatha or a vipashyana angle, or both.
1)Integration is associated with concentration meditation, such as mindfulness of breathing.
2)Positive emotion comes about through loving kindness (Metta Bhavana) meditation and the family of practices Metta Bhavana comes from, i.e. the Four Brahmaviharas.
3)Spiritual death is arrived at through vipashyana meditations such as the Contemplation of Conditionality or the Six Element practice.
4)Spiritual rebirth is especially associated with sadhana or visionary imagination of the Buddha, traditionally known as Buddhanusmrti – ‘mindfulness of the Buddha’. Sadhana is often a complex of practices within practices, a mandala with the Buddha at the centre. An important aspect is the active cultivation of the Buddha’s qualities of wisdom and compassion. Hence this phase of the system of meditation, like the three foregoing ones, can be associated with the Active approach. However since sadhana also especially involves receptivity to the living qualities of the Buddha, it also links very naturally to the Receptive approach.
5) Mindfulness has the unique place in our system of making sure the meditator does not lose his or her grounding in tangible, felt experience through over emphasising the active approach. Mindfulness refers to many different kinds of practice, but in terms of meditation it is especially associated with Just Sitting. More will be said in Chapter Three, but the essence of this approach is to stop doing things and come into relationship with immediate experience. The effect on the practice is refreshment and renewal at every level.