Water Baptism vs. the Baptism of the Holy Spirit

There is much confusion about a second experience with the Holy Spirit after salvation. Some teach that believers must earnest seek a baptism of the Holy where one receives a “filling” or baptism of the Holy Spirit. Is this something every Christian should seek for? Is it Biblical? What is the baptism of the Holy Spirit? When does it occur? Who is it for? What more can I learn about the person and work of the Holy Spirit?