We have used the Westerbork array to carry out an unbiased wide-field survey of H i emission features , achieving an rms sensitivity of about 18 mJy/Beam at a velocity resolution of 17 km s ^ { -1 } over 1800 deg ^ { 2 } 
and between -1000 ~ { } < ~ { } V _ { Hel } ~ { } < ~ { } +6500 km s ^ { -1 } .
The primary data consists of auto-correlation spectra with an effective angular resolution of 49 ^ { \prime } 
FWHM .
The survey region is centered approximately on the position of Messier 31 and is Nyquist-sampled over 60 \times 30 ^ { \circ } in R.A . \times Dec .
In this paper we present our H i detections at negative velocities which could be distinguished from the Galactic foreground .
Fully 29 % of the entire survey area has high velocity H i emission at a column density exceeding our 3 \sigma limit of about 1.5 \times 10 ^ { 17 } cm ^ { -2 } 
over 30 km s ^ { -1 } .
We tabulate the properties of 95 discrete HVC components in the field , corresponding to more than an order of magnitude increase in number over that known previously .
The distribution of discrete object number with flux density has an inflection point near 12 Jy-km s ^ { -1 } which may correspond to a characteristic mass and distance for this population .
A faint population of discrete HVCs is detected in the immediate vicinity of M31 which spans a large fraction of the M31 rotation velocity .
This class of features is confined to about 12 ^ { \circ } ( 160 kpc ) projected radius of M31 and appears to be physically associated .
Independent confirmation of the features within 3 . ^ { \circ } 5 ( 47 kpc ) of M31 has been obtained in our Green Bank Telescope survey ( Thilker et al . [ ] ) .
We detect a diffuse northern extension of the Magellanic Stream ( MS ) from at least \delta = +20 \rightarrow 40 ^ { \circ } , which subsequently loops back toward the south .
Recent numerical simulations had predicted just such an MS extension corresponding to the apo-galacticon portion of the LMC/SMC orbit at a distance of 125 kpc .
A faint bridge of H i emission appears to join the systemic velocities of M31 with that of M33 and continues beyond M31 to the north-west .
This may be the first detection of H i associated with the warm-hot intergalactic medium ( WHIM ) .
The distribution of peculiar velocity H i associated with M31 can be described by a projected exponential of 25 kpc scale-length and 5 \times 10 ^ { 17 } cm ^ { -2 } 
peak column density .
We present the distribution function of N _ { HI } in the extended M31 environment , which agrees well with the low red-shift QSO absorption line data over the range log ( N _ { HI } ) = 17.2 to log ( N _ { HI } ) = 21.9 .
Our data extend this comparison about two orders of magnitude lower than previously possible and provide the first image of the Lyman limit absorption system associated with an L _ { * } galaxy .