We know surprisingly little about how, when and where quasars are triggered as
galaxies evolve. In this seminar I will review quasar triggering mechanisms,
and present the results from an optical and far-infrared study of a large sample
luminous radio-loud AGN that cast direct light on the quasar triggering issue,
demonstrating that galaxy mergers are the most likely triggering mechanism.
Along the way, I will emphasise the importance of taking full account of the
AGN-related continuum components when determining the host galaxy
properties. Also, I will discuss the reasons for the apparent dearth of star
formation activity in the most luminous AGN.