The book starts with a short history of monastic brewing generally and brewing by the Trappist order in particular. The beers from just seven monasteries carry the Authentic Trappist Product marque, denoting that they either brewed within a Trappist abbey or under the control Trappist monks. Many commercial breweries have used monastic associations; their products are usually termed “Abbey Beers” though some, such as St Bernardus, have tenuous links with genuine Trappist breweries.

Rob then gives us a detailed guide to the six Belgian Trappist breweries – Achel, Chimay, Orval, Rochefort, Westmalle and Westvleteren (the seventh, Koningshoeven, is in Holland and responsible for the Le Trappe beers). There's a short brewing history for each monastery, followed by detailed descriptions of all the commercially available brews (four of the abbeys produce weaker Patersbiers for consumption by the monks). The descriptions take in colour, aroma, taste and aftertaste and convey superbly the delights and complexities of these mostly wondrous beers, without resorting to the “Jilly-speak” favoured by some beer writers (“redolent of the inside of empty cigar boxes” - that kind of thing)

Rob is rightly enthusiastic about the Achel beers, which are insufficiently well known, probably because they only restarted brewing in 1998. He's kinder to Chimay than I'd have been – for me, their beers lost their edge some time ago. The classic Orval is very well portrayed; as Rob says, both the colour and aroma might well put off the newcomer as might the initial, almost sour, taste, but once you get accustomed to it, there's no looking back. Of the Rochefort beers, the 6 can be the trickiest to find which is a shame as proven by Rob's enthusiastic review. He approaches the legendary 10 (at 11.3% the strongest Trappist beer) from the position of it being his least favourite of the genre but, after an intensive tasting, decides that he understands the acclaim for it whilst retaining reservations about its modest hop presence. The two Westmalle beers are well liked though Rob confesses that Dubbel isn't a style he personally goes for. No doubts about the fabulous Tripel though where he picks out the banana, vanilla and spice flavours which contribute to the intricate end result.

Finally to the enigma that is Westvleteren. This is by far the least commercial of the breweries and their beers are hard to locate – you can get them at the monastery itself but only after first jumping through a myriad of hoops or, in limited quantities, from the Visitor Centre (but they're often sold out). A handful of specialist beer shops and cafes such as Cambrinus in Bruges sometimes have bottles, albeit at a hefty price, and this is how Rob tracked the three beers down. He's underwhelmed by the Blond but enraptured by the 8 - “without doubt a great beer”. So, lastly, to the 12, which the influential Rate Beer website declared in 2005 to be the Best Beer in the World. I must confess that when I first tasted it many years ago I was inclined to agree though, nowadays, I've got greater favourites. Anyway, Rob concludes that it's “an enjoyable beer, but it does become sweet and sherry-like” - “not the greatest beer in the world, although it may well be the most sought after”.

The booklet ends with a list of recommended further reading. If you enjoy Trappist beers (and if not, why not?) then this is a near-definitive and mouth-watering account – it had me soon reaching for the nearest bottle of Westmalle Tripel. The book is available from the Elm Tree price £8.

And if you're intrigued by Westvleteren 12, see the competition elsewhere in this issue.