Author: 永田浩史・小林健史
Publisher: 秀和システムトレーディング株式会社 (Shuwa System Trading Co., Ltd.)
Publication date: 1990/9/7
Number of pages: 182
Price: ¥1553
Price (tax included): ¥1600
There are several variants of this book. I know three versions (there are probably others):
A scanned PDF of this book is available here: http://mocagh.org/loadpage.php?getgame=dm-x68k
You may browse this book and download a PDF file at https://archive.org/details/dungeonmasterguidebook/mode/2up