Full Idea
A sequent calculus is a useful tool for comparing two systems that at first look utterly different (such as natural deduction and semantic tableaux).
Gist of Idea
A sequent calculus is good for comparing proof systems
Source
David Bostock (Intermediate Logic [1997], 7.2)
Book Reference
Bostock,David: 'Intermediate Logic' [OUP 1997], p.281