Thin-Layer Chromatography (TLC) is a form of liquid chromatography utilizing a flat open separation surface, which has been used in laboratories for over 70 years. The official IUPAC term “planar chromatography”, covers all chromatographic techniques using a planar open stationary phase: thin-layer chromatography (TLC), high-performance thin-layer chromatography (HPTLC), ultrathin-layer chromatography (UTLC), and preparative layer chromatography (PLC). HPTLC is the most powerful analytical version of this form of chromatography. The International Symposium for HPTLC is fully dedicated to all aspects of this high performance method of liquid chromatography.