Marcus demonstrated that it was possible to construct a deterministic grammar/interpreter for a subset of natural language [Marcus, 1980]. Although his work with PARSIFAL pioneered the field of deterministic natural language parsing, his method has several drawbacks: • The rules and actions in the grammar / interpreter are so embedded that it is difficult to distinguish between them. • The grammar / interpreter is very difficult to construct (the small grammar shown in [Marcus, 1980] took about four months to construct). • The grammar is very difficult to maintain, as a small change may have several side effects. This paper outlines a set of structure transformations for converting a non-deterministic grammar into deterministic form. The original grammar is written in a context free form; this is then transformed to resolve ambiguities.