Slightly more affordable than Pieper-Heidsieck (see other item in this Brief) is The Champagne Warrior. Brad Baker is the self-appointed champagne warrior. One has to conclude that he is a champagne fanatic, and he publishes a newsletter on champagne, called The Champagne Warrior. It contains articles, both short and long, on champagne related subjects as well as extensive tasting notes. In issue #7 (extending over more than 70 pages) you can read about e.g. champagnes with little or no dosage, about the legendary Clos des Goisses from Philipponnat (and how Baker by chance became the happy owner of a whole assortment of such bottles), and an interview with Anselme Selosse. If you don’t mind wading through the quite lengthy tasting notes there is quite a lot of interesting and useful information. A subscription will set you back $90; you can get a sample issue for $1. More info here https://www.champagnewarrior.com/