The second edition of this book is primarily designed for senior undergraduatestudents wishing to pursue a course in Lattices/Boolean Algebras. It deals withpartially ordered sets, duality principle, isomorphism, lattices, sublattices,ideals (dual, principal, prime), complements, semi and complete lattices. Italso contains results pertaining to modular and distributive lattices anddiscusses various topics related to Boolean algebras (lattices) includingapplications. Theoretical discussions have been amply illustrated by numerousexamples and worked-out problems. Hints and solutions to selected exercises havebeen added as a further help.