1. Introduction, preliminaries. We shall extend results of Samuel [19] and Griffin [8,9] about conditions which generalise the notion of valuation domain in a field. Let U be a commutative ring with identity, R a subring of U and L an /?-submodule of U. The conditions we study have in common the property (EV), that the submodules L:x (x e U) form a chain. We pay particular attention to the strongest of the conditions, viz, that L be a Manis valuation (MV) subring, i.e. having a prime ideal P such that (L, P) is a maximal pair in U (see [19], [16] and e.g. [4]). Such P is unique, being the union of all L:x such that x $ L, which we call P+{L) the centre of L. This set P+ plays a key role in the study of all our valuation conditions.The main definitions are in Section 1. In Section 2 basic results on localisation and factoring by a (/-ideal are followed by applications. Samuel's result [19, Theoreme 5] that if (R, P) is (MV) then R satisfies the Bourbaki condition (BV), defined in Section 1.2, is extended to the case where P is replaced by a finite chain of prime ideals. In Section 3 we show that if R is (BV) then prime R-ideals containing P+{R) are also (BV). The method gives new criteria for a submodule to be (BV). In Section 4, when L is (EV), we discuss the evaluation map v L given by v L (x) = L:x. Our main interest is in the cases L = P+(R), used in [16] to characterise (MV) rings, and L = R mentioned in [8]. At the end we discuss the relation, given in [8], between (BV) rings and evaluations with cancellative image.