Relevant parameters and stereochemical consequences of helices la-helix, [alpha--helix, beta-bend ribbon spiral, gamma-helix, 2.0(5)-helix, poly(Pro)(n) type-I and -II helices, and collagen triple helix] of peptides based on alpha-amino acids for use as templates in various branches of chemistry are briefly discussed. (C) 2005 Wiley Periodicals, Inc.