A lawyer or attorney is a person who practices law, as an advocate, attorney, attorney at law, barrister, barrister-at-law, bar-at-law, civil law notary, counsel, counselor, counsellor, counselor at law, solicitor, chartered legal executive, or public servant preparing, interpreting and applying law, but not as a paralegal or charter executive secretary. Working as a lawyer involves the practical application of abstract legal theories and knowledge to solve specific individualized problems, or to advance the interests of those who hire lawyers to perform legal services.