I just finished Planet of the Umpires by Ken Kaiser (with Dave Fisher) and it was a fine read but nothing special. I felt like I was reading another Ron Luciano book since the co-author was the same for both.

I personally think two of the funniest baseball books of all time are The Umpire Strikes Back by Ron Luciano (with Dave Fisher) and Catcher in the Wry by Bob Uecker.

Their baseball stories are funny and well written.