Sima Ziyan : Original name : Zhang Zu Chuan, his pseudo name is Sima, was bornt in Anhui. Graduated from Taiwan Normal University. During his study time, he ghostwriting a story called 《江湖夜雨十年灯》 (Jianghu night rain, a decade light? ) using a nickname of Zhuge Qing Yun (诸葛青云). In 1963, this story was published in Hongkong Mingbao. Jin Yong gave the name Sima Zi Yan instead of Zhuge Qing Yun for the author name of 江湖夜雨十年灯. His writing style is smooth and flowing, magical closely like that of Huan Zhu Lou Zhu, simple and straightforward like that of Wang Dulu. Pity he died young. He wrote about two dozens of novels before passed away.
Regarding 《江湖夜雨十年灯》, Zhuge Qingyun was the original author, but he didn't finish writing it. Instead, Sima Ziyan, Gu Long, and Ni Kuang all contributed chapters to finish the novel. I'm not sure how much each person wrote. Note that this was before Gu Long was famous, before his style changed to what he is known for today.
This novel was reprinted just last year, so is readily available.