Robert H. Lessin, longtime Wall Street banker and technology angel investor, passed away August 8.  He was 56.  His passing was disclosed in a note sent to employees of Jefferies & Company, where he had been vice chairman.  Cause of death was not mentioned, although it's understood that he had had a long illness.

Lessin spent three decades as an investment banker, while holding senior positions at Morgan Stanley, Salomon Smith Barney and Wit Capital. After graduating from Harvard B-School, he soared through the ranks at Morgan Stanley, and became the firm's youngest partner ever in 1987.

He moved on to become vice chairman at Salomon Smith Barney and led the firm's investment bank. There he became increasingly involved in technology, and was one of the first angel investors on the East Coast. In 1998, he left to focus more on tech, which led him to Wit Capital.

After joining boutique tech investment bank Wit Capital, Lessin founded venture capital fund Dawntreader Ventures.  In 2002, he met with Richard Handler, CEO of Jefferies, and walked out with a job despite no offer being on the table.

He is survived by his wife, Clara Wong, and his children, Daniel, Kara and Sam Lessin. [Dealbook, 8/9/11]