The very good results achieved at the first five undulator beamlines commis
sioned at BESSY II showed that thoroughly developed aspects for a general c
onception for the realization of new undulator beamlines for BESSY II have
paid off. Basic ideas like an optical design with the possibility to employ
optical elements with highest precision and simple drives combined with a
very precise position control as well as an indispensable metrology laborat
ory of highest quality have been the key for success. (C) 2001 Elsevier Sci
ence B.V. All rights reserved.