In the first nine editions, artists were listed alphabetically and the entries began with short (usually one paragraph)
biographies before a comprehensive listing of a musicians' available
recordings in the United Kingdom at that time. Each disc was given a rating of up to four stars and details of its label and catalogue number, musicians featured on the disc, month and year of the recording or the span of time in which the tracks were recorded and finally a review of varying length. Often a number of discs were reviewed together. Two extra features, author's picks (crowns) and "core collections", were added to succeeding editions. The first showed entries flagged as personal favorites while the latter made special note of the "more essential" albums for a jazz CD collection. John Eyles comments in a review that "the implication is that the choices for crowns are subjective, while the Core Collection is somehow more objective", when in fact both lists are decided upon by the same two editors. Bootlegs and limited-edition
Mosaic Records releases were excluded. Some various-artists compilations were reviewed in the first edition but were dropped in later editions. Due to the increasing numbers of CDs on the market, space limitations and depth of coverage became an increasing problem: in the seventh edition, for instance, the
index was dropped to save space, but it was restored in the eighth edition (though a number of entries were dropped or shortened to make room for it). In the 10th edition, titled
The Penguin Jazz Guide (2010), Morton revised his and Cook's entries from previous editions, and pared down the content to 1001 reviews of what Morton had selected as the best jazz recordings. == Reception ==