If you have made it to here, we hope that you have enjoyed the journey. The test of the value of the journey is whether, as you gained some new insights, you looked at your pet cat or dog or at animals at a zoo in a different way. Most importantly, if you are contemplating a scientific study, hopefully you have acquired some new insights into the process by which to decide what may be the most profitable aspects of the behaviour to measure. What we have offered is a glimpse into the factors that contribute to how behaviour is organised and have, hopefully, shown how abstracting behavioural markers can be rendered into a more objective process. Even if derived from a formal application of the principles that underlie the organisation of behaviour, once multiple researchers apply them, some behavioural markers will weather the test of time but others will not. In the latter case, the proposed markers will be found to be poor reflections of the organisation they are meant to represent. That is what science is all about; some hypotheses stand up to scrutiny and some do not.