\begin{abstract}
A notion called {\em Herbrand saturation} is introduced, and is shown to provide the model-theoretic analogue of a proof-theoretic method, Herbrand analysis. This provides uniform and sometimes simplified model-theoretic proofs of a number of important conservation theorems, and helps clarify the relationship between semantic and syntactic methods. A constructive, algebraic variation of the new method is described, providing yet a third approach, which is finitary but retains the semantic flavor of the model-theoretic version.
\end{abstract}