I just updated the ebook. It is now version 3.40.
Buyers can download the revisited book everytime on the digital shelf at Lybrary.com.

I’m probably going to get reprimanded for saying this but I think if you’re posting something like this, a link should be included. Even the lybrary.com link isn’t live.

Just a bit of a standard marketing/sales tip since this post is 100% about a product anyway. It’s probably just me but these posts promoting something then leaving you hanging are irritating, which I don’t think is your goal.

https://www.lybrary.com/melencolia-p-921956.html

Some of us are glad that it's not too simple for everyone to access this gem of a book.

Dear Chris K,

Thank you very much for your advice. In principle, you are right.
Thank you very much for setting the link.

But, it's not my intention to advertise anything in TMC. I don't care about sales - I know this is unusual here - my wage is only a few cents/book page anyway. I even give away my books to those who are GENUINE interested or work in the field but can only rarely afford books. (Unfortunately, at present there are more affected magicians than many think.)

I just wanted to inform those who own my book about an updated version. The book-owners usually know where they can find the update.

At the end of November 2020, I will update the ebook. It will be version 3.50.

Buyers can download the revisited book on the digital shelf at Lybrary.com.
https://www.lybrary.com/melencolia-p-921956.html

The revision's focus is on birthday squares, historical references, and the removal of inaccuracies and small errors.

I acknowledge from the bottom of my heart that it is likely that all fundamental ideas for constructing magic squares were already thought of more than 500 years ago by great minds!

Updated.

I have extensively revised part III - 5x5 magic squares and the chapter about the magic birthday square, and much more. “Melencolia I - Magic Squares for the Mental Entertainer” now has 176 A4-pages. Many methods have never been described before.

The price will rise to 45 USD in 2021, and it is then still a bargain.

Apart from Jim Solberg’s great and amazing trilogy “Magic Square Methods and Tricks,” it is the most comprehensive book about smart methods for 4x4, 5x5, and 6x6 magic squares.

Find Melencolia I and the updated table of contents here:
https://www.lybrary.com/melencolia-p-921956.html

Hint: purchasers can freely download the update from their permanent link on the digital shelf at Lybrary.com.

Anyone who is interested in magic squares should get this e-book now. It is loaded with innovative ideas, and is a bargain because it started as a much shorter manuscript and grew with additions since then. Hans-Christian has been very generous in not raising the price or publishing the additions as separate e-books. It will still be a good buy at the higher price.

(If you are still using the standard old method for 4x4 squares, you should be aware that there are several much better methods now.)

Errata in v. 3.50

p. 20
"I use a spectator’s age older than 39 years for the magic sum to avoid duplicate numbers."
correct is:
"I use a spectator’s age older than 45 years for the magic sum to avoid duplicate numbers."