 In textbook presentations, quantum mechanics is about measurement outcomes performed when an “observer” makes a “measurement” on a quantum system. What is an observer, if all physical systems are quantum? What counts as a measurement? Common answers invoke the observer being macroscopic, onset of decoherence, irreversibility, registration of information, or similar. RQM does not utilise anything of the sort. Any system, irrespectively of its size, complexity or else, can play the role of the textbook’s quantum mechanical observer. The “measurement outcomes” of a given observer, however, refer only to values of the variables of the quantum system relative to that system. In particular, they do not affect events relative to other systems. In the same spirit, textbook presentations of quantum mechanics refer to “measurement outcomes”. In the relational interpretation, any interaction counts as a measurement, to the extent one system affects the other and this influence depends on a variable of the first system. Every physical object can be taken as defining a perspective, to which all values of physical quantities can be referred.