a master of：...的大师；某方面掌握的好，用have a good master of...；成为自己命运的主人，用to be a master of my own destiny。

【例句】
He's a real craftsman. He's a master of his craft.
他有一手好手艺。

I wish I could be a master of this subject.
但愿我能精通这门学科就好了。