In this paper , we describe the design and data analysis of the DEEP2 Galaxy Redshift Survey , the densest and largest high-precision redshift survey of galaxies at z \sim 1 completed to date .
The survey was designed to conduct a comprehensive census of massive galaxies , their properties , environments , and large-scale structure down to absolute magnitude M _ { B } = -20 at z \sim 1 via \sim 90 nights of observation on the Keck telescope .
The survey covers an area of 2.8 deg ^ { 2 } divided into four separate fields observed to a limiting apparent magnitude of R _ { AB } = 24.1 .
Objects with z \lower 2.15 pt \hbox { $ \buildrel < \over { \sim } $ } 0.7 are readily identifiable using BRI photometry and rejected in three of the four DEEP2 fields , allowing galaxies with z > 0.7 to be targeted \sim 2.5 times more efficiently than in a purely magnitude-limited sample .
Approximately sixty percent of eligible targets are chosen for spectroscopy , yielding nearly 53,000 spectra and more than 38,000 reliable redshift measurements .
Most of the targets which fail to yield secure redshifts are blue objects that lie beyond z \sim 1.45 , where the [ O II ] 3727 Ã Â doublet lies in the infrared .
The DEIMOS 1200-line/mm grating used for the survey delivers high spectral resolution ( R \sim 6000 ) , accurate and secure redshifts , and unique internal kinematic information .
Extensive ancillary data are available in the DEEP2 fields , particularly in the Extended Groth Strip , which has evolved into one of the richest multiwavelength regions on the sky .

This paper is intended as a handbook for users of the DEEP2 Data Release 4 , which includes all DEEP2 spectra and redshifts , as well as for the DEEP2 DEIMOS data reduction pipelines .
Extensive details are provided on object selection , mask design , biases in target selection and redshift measurements , the spec2d two-dimensional data-reduction pipeline , the spec1d automated redshift pipeline , and the zspec visual redshift verification process , along with examples of instrumental signatures or other artifacts that in some cases remain after data reduction .
Redshift errors and catastrophic failure rates are assessed through more than 2000 objects with duplicate observations .
Sky subtraction is essentially photon-limited even under bright OH sky lines ; we describe the strategies that permitted this , based on high image stability , accurate wavelength solutions , and powerful b-spline modeling methods .
Summary data are given that demonstrate the superiority of DEEP2 over other deep redshift surveys at z \sim 1 in terms of galaxy numbers , redshift accuracy , sample number density , and amount of spectral information .
We also provide an overview of the scientific highlights of the DEEP2 survey thus far .