  We present the Observations of Redshift Evolution in Large Scale Environments
(ORELSE) survey, a systematic search for structure on scales greater than 10
Mpc around 20 well-known clusters at 0.6 < z < 1.3. We describe the survey
design, the cluster sample, and our extensive observational data covering at
least 25' around each target cluster. We use adaptively-smoothed red galaxy
density maps from our wide-field optical imaging to identify candidate
groups/clusters and intermediate-density large scale filaments/walls in each
cluster field. Because photometric techniques can be highly uncertain, the
crucial component of this survey is the unprecedented amount of spectroscopic
coverage. We are using the wide-field, multi-object spectroscopic capabilities
of the DEep Multi-Object Imaging Spectrograph to obtain 100-200+ confirmed
cluster members in each field. Our survey has already discovered the Cl 1604
supercluster at z = 0.9. Here, we present the results on two additional
clusters, Cl 0023+0423 at z = 0.84 and RX J1821.6+6827 at z = 0.82. The
optically-selected Cl 0023+0423 is a four-way group-group merger with
constituent groups having velocity dispersions between 206-479 km/s. The galaxy
population is dominated by blue, star-forming galaxies, with a substantial
contribution from recent starbursts. In contrast, the X-ray-selected RX
J1821.6+6827 is a largely-isolated, massive cluster with a measured velocity
dispersion of 926 +/- 77 km/s. The cluster exhibits a well defined red sequence
with a large quiescent galaxy population. The results from these two targets,
along with preliminary findings on other ORELSE clusters, suggest that optical
selection may be more effective than X-ray surveys at detecting less-evolved,
dynamically-active systems at these redshifts. [Abridged]
