Grant1978,
if you are looking into how maintenance is conducted then a step back from the physical act of maintenance is maintenance planning, or more importantly Continued Airworthiness and the relationship between the organisation responsible for the airworthiness of an aircraft and the engineering team that do the work.
Its a series of approvals under EASA, PART-M for airworthiness, PART.145 for engineering & PART-66 for engineering approvals.