 In the first book, Button and Walsh 2018, the authors present an invitation to the reader to help create a discipline, ‘philosophy and model theory’, which is gradually coming into existence.  (This is partly belied by the large amount of carefully-worked material in the book.)  Mathematics in general is a source of fundamental philosophical worries.  For example mathematicians refer to entities that we have no causal interaction with (such as the number π or the set of real numbers), and this creates questions about how we can identify these entities to ourselves or each other, and how we can discover facts about them. These problems are not new or peculiar to model theory; but mathematical model theory is the part of mathematics most concerned with ‘reference’ and ‘isomorphism types’ and ‘indiscernibility’, notions which go directly to the philosophical problem areas.  The authors give clear analyses of exactly what the issues are in key discussions in these areas.