Chapter three of the yoga sutras of Patanjali moves into more cerebral practices. In this first sutra of Vibhuti pada, there is an exploration of how Patanjali describes concentration (the sixth limb of the ashtanga system).
Concentration is the preliminary practice for meditation. Mediation will evolve naturally out of a sustained practice of concentration.
As well as an interpretation of this sutra a short practice of concentration is offered which will be of particular use for anyone trying to develop a meditation practice.