Just finished listening to this. An absolute cornerstone of the New Wave Of British Heavy Metal.
It was originally released in 1986, this is a 1987 reissue of that release, but's actually a remastered and augmented release of their 1980 limited run debut album which is currently selling for $440 on discogs.
Sleeve notes written by Lars Ulrich who basically acknowledges that Metallica learned how to write music based on Diamond Head's early work.
Diamond Head ~ Behold The Beginning
1987 Metal Blade Records 72200-1
https://www.discogs.com/Diamond-Head-Behold-The-Beginning/master/181613