Montgomery, Captain John Berrien

US naval captain, of the USS Portsmouth, who raised the US flag over the Plaza of San Francisco in 1846.

https://en.wikipedia.org/wiki/John_B._Montgomery

Richardson, William A.

British sailor and early California colonist; founder of San Francisco and Saucelito.

http://www.foundsf.org/index.php?title=WILLIAM_RICHARDSON_AND_YERBA

https://en.wikipedia.org/wiki/William_A._Richardson

Crowley, Thomas

Asbury thanks Thomas Crowley, among others, for help with sources for his book The Barbary Coast. This is perhaps the same Thomas Crowley who began as a whitehall boatman on San Francisco Bay, and went on to found Crowley Maritime.

http://www.crowley.com/About-Us/History
https://en.wikipedia.org/wiki/Crowley_Maritime

In 1967, Crowley sat for an oral history interview on his recollections of San Francisco's waterfront:

digitalassets.lib.berkeley.edu/roho/ucb/text/crowley_thomas_waterfront__w.pdf

McGee, Patrick

Asbury thanked police Sergeant Patrick McGee among his sources for the book. McGee was a long-time police officer, who had joined the force before the Spanish-American War. He wrote a history of the San Francisco Police Department in 1928.

Boland, James

"Policeman James Boland and friends" (San Francisco Public Library). The man to Boland's right looks a bit like Herbert Asbury.

Asbury listed police Lieutenant James Boland among those he thanked as sources for his book The Barbary Coast. A year after the book was published, Boland would be acting chief, overseeing a hunger strike by political prisoners in the aftermath of the 1934 general strike.

"Acting Police Chief James Boland showing a gun" to Mayor Rossi and other members of a "crime commission." (San Francisco Public Library)

Quinn, William J.

William J. Quinn, from sanfranciscopolice.org

William J. Quinn was San Francisco Chief of Police at the time of Asbury's research. He reportedly had started off his career as a beat cop on the Barbary Coast.

http://www.onlinebiographies.info/ca/sf/quinn-wj.htm
https://en.wikipedia.org/wiki/William_J._Quinn

Fay, Luke

Luke Fay was a longtime San Franciscan and heir to a soapmaking fortune. He was an amateur historian interested in early San Francisco, and is listed by Asbury as one of his sources for the Barbary Coast.

More information on the Fay family:

https://rhnsf.org/history/houses/the-fay-berrigan-residence/

Behslich, Dean

Dean Behslich is listed by Asbury as one of his sources of information for the Barbary Coast. At this time I have not found any further information about him.

Older, Fremont

The legendary San Francisco journalist and newspaper editor Fremont Older was one of those thanked by Asbury as one of the sources of information for the Barbary Coast.

https://en.wikipedia.org/wiki/Fremont_Older

Gleeson, Edward T.

Edward T. Gleeson, an editor of the San Francisco Call, was one of the sources thanked by Asbury in his introductory Author's Note.

Jones, Idwal

Idwal Jones is one of those listed in thanks by Asbury at the beginning of the book. Jones was a novelist who wrote historical fiction set during the Gold Rush, as well as a history of the Montgomery Block.

https://en.wikipedia.org/wiki/Idwal_Jones_(novelist)

Asbury, Herbert

Herbert Asbury (Image from the Daily Journal Online)

As numerous sources will tell you, the journalist Herbert Asbury, author of The Barbary Coast, was more attuned to a colorful story than to historical accuracy. Thus, a major focus of this Annotated Barbary Coast (ABC) will be to tease out, whenever possible, just what in his book can reasonably be believed to be accurate, what can not, and where between these two poles the rest lies.

More details of his life and writings can be found online:

https://en.wikipedia.org/wiki/Herbert_Asbury

I am not (yet) aware of any sustained investigation into Asbury's life. A good many writers, mostly commenting on his Gangs of New York, hold him at arm's length--noting his inaccuracies and errors, while still relying on him when convenient.