Interesting catalog announcement from Michel

On 5 April 2019 Michel published a new catalog titled MICHEL Raritäten: Marken, die Sie kennen sollten! Cost is around 30 Euros. To quote from their English prospectus:

So you can join the debate: MICHEL introduces issues that are either world-famous, extremely pricey or extraordinary in other aspects.

First edition!
    History, development of the value in the past decades and things worth knowing regarding significant stamps from around the world
    A “must-know“ for anyone interested in “social philately“: issues that have been well-known or famous for a long time as well as those that are currently “hot“
    All chapters are illustrated with high-resolution colour pictures, diagrammes and other graphs
    Extensive background stories and further details
    Perfect for collectors and everyone who wants to become a collector.

Presumably there will be few stamps in this catalog that are in the Big Blue (perhaps US #1 and 2) so why mention it here? Well, for one, I think it is an interesting concept which would, of course, be relevant to those working on the Brown Internationals.

But, second, is the intriguing end of the prospectus:

"The exciting launch of the new MICHEL Rarities series that focuses on highlights of philately. The second volume, featuring first issues worldwide, will follow in December [2019]." Now number ones of the world is surely a topic that would be interesting to many of us.