  Left-sequential logics provide a means for reasoning about (closed)
propositional terms with atomic propositions that may have side effects and
that are evaluated sequentially from left to right. Such propositional terms
are commonly used in programming languages to direct the flow of a program. In
this thesis we explore two such left-sequential logics. First we discuss Fully
Evaluated Left-Sequential Logic, which employs a full evaluation strategy,
i.e., to evaluate a term every one of its atomic propositions is evaluated
causing its possible side effects to occur. We then turn to Short-Circuit
(Left-Sequential) Logic as presented in [BP10b], where the evaluation may be
'short-circuited', thus preventing some, if not all, of the atomic propositions
in a term being evaluated. We propose evaluation trees as a natural semantics
for both logics and provide axiomatizations for the least identifying variant
of each. From this, we define a logic with connectives that prescribe a full
evaluation strategy as well as connectives that prescribe a short-circuit
evaluation strategy.
