Briefing: Gather together: Photographer Neal Slavin on what 50 years of taking group shots says about usBriefing: Gather together: Photographer Neal Slavin on what 50 years of taking group shots says about usBriefing: Gather together: Photographer Neal Slavin on what 50 years of taking group shots says about us

Strategic angle: Neal Slavin's landmark photography book "When Two or More Are Gathered Together" reveals the many sides of 20th century American society and is notably for its use of colour.