I opened both listings on Amazon.de in October 2026. The adult book is Lesson Book, Level One, 111 pages, English. The children's book is Lesson Book Level 1A, 64 pages, English. Confirm the cover before you buy. I am not linking a German method until I have checked that exact edition.
Read the cover before the title
Lesson book is the course. Theory, technique, recital and all-in-one are different books. Level 1 is not the first book in every series. In Alfred's Basic Piano Library the start is Level 1A. Level 2 continues after 1B, and it is a different listing.
Both books below are in English. A child who does not read English will not practise from them. Piano Kids, the European Piano Method and several others are the usual German choices. Ask me which one fits. I would rather name it in a message than link an edition I have not checked.
Adults, from the first note · Entry-level budget
Alfred's Basic Adult Piano Course, Lesson Book Level 1
“Adults do better in a book written for them. This one starts at the first note and brings in chords early.”