I'm also looking forward to this book. The man was CO of III./StG 1 and the Knight's Cross holder by July 1941.
Generally speaking, there won't be many new memoirs of that kind, for obvious reasons (Herr Mahlke passed away in 1998, aged 85). However, there are still many memoirs and unit histories in German, waiting for English translation. I'm sure many of them would be instant hits (a hint for publishers if you read this
)