"Great swashbuckling stories!" [KF])
Thorndyke (sometimes spelled Thorndike), Arthur Russell 
1885-?      Doctor Syn series: After his wife is kidnapped by 
pirates, an English cleric takes to the high seas in pursuit of 
them. In the process, he assumes the persona of a pirate, 
Captain Clegg, captain of the Imogene (named for his wife, 
I think). He eventually hunts the pirates down only to learn 
that his wife is dead and that a price has been placed on his 
head by King George. After some years, and two books,
of high seas adventures, he returns to rural England to shed 
his past and assume a posting as vicar of Dymchurch. He is 
accompanied, however, by      his former ship's carpenter, 
Mr. Mipps, who quickly becomes involved in the local 
smuggling ring. Dr. Syn, fearing for the life of his friend and
others, decides to bring the ragtag group of smugglers 
together by becoming their masked leader, The Scarecrow 
of Romney Marsh. The remaining books in the series address 
his adventures as leader of this group, and the Crown's efforts 
to capture and kill him.  An interesting aspect of the character 
is his very minimal interest in the "big picture": the impact of, 
say, his pirating activities on global economics does not 
interest him.  Likewise, his smuggling activities 
aren't intended as a political statement against high 
taxes or the war between England and France.
Another point to note: there isn't really a clear-cut battle
between good and evil, the Scarecrow's foes being frequently
as sympathetic and yet as ruthless as he is.
        (Incidentally, "Christopher Syn" and "Dr. Syn, alias the Scarecrow" are not canon)
"Perhaps the least known in the U.S. are the books about a 
country parson, the Reverend Dr. Christopher Syn, D.D.
(Doctor of Divines), LL.D., etc., the Vicar of Dymchurch, 
Romney Marsh (in Kent, England), who is also the pirate 
"Captain Clegg" and the smuggler-highwayman and masked 
avenger called "The Scarecrow". He is a sinister and 
mysterious person, a brilliant scholar at Oxford, a gallant lover 
and duelling cavalier, who became a pirate for revenge - but 
who never attacked a British ship. 

He led a "triple life" and became a rebel against King 
George III; protested harsh taxes, naval press gangs, and 
other tyranny and oppression; and supported the American 
rebels. Dr. Syn (pronounced "sin"), was also the head of the smugglers in southeastern England. A relentless righter of 
wrongs, Syn went around rescuing, defending, and avenging 
the wronged. Later, he helped French refugees get to England 
(um, isn't that Blakeney's line of work?) and fought French ships 
and pirates. His long career lasted from the 1750's to 1808, 
when he was killed."  (Thanks to the Naval Gazette).
List of books: 
       Doctor Syn, 1915 (set in either 1784 or 1808, deals with 
Syn's discovery and capture at the end of his career.  He is
is portrayed as appealing but ruthless and doomed.  Plot 
resembles that of the Arliss and Cushing films based on it)
       Dr. Syn Returns, 1935 (set in 1775, the middle-aged Syn 
first dons the Scarecrow guise.  There's a strong element of 
altruism in his motives, softening the character's grimness)
       The Scarecrow Rides, 1935 (unknown, may be a reprint 
under another title of Dr. Syn Returns)
       Further Adventures of Dr. Syn, 1936 (set in 1776, 
apparently involves the American Revolution)
       Dr. Syn on the High Seas, 1936 (set in 1754, deals with 
young Syn's becoming the Dread Pirate Clegg)
       Amazing Quest of Doctor Syn 1938 (set in 1780 or 1790, 
is either another `Clegg' book, or deals with Syn acquiring a 
love interest or a long-lost daughter)
       Courageous Exploits of Dr. Syn, 1939 (set in 1781, 
episodic series of Scarecrow adventures, unified by one 
main antagonist)
       Shadow of Doctor Syn, 1944 (1793, apparently Syn's last adventures prior to his destruction in the first book)
       Christopher Syn, 1960 (an American named Buchanan
substantially rewrote "Further Adventures", apparently with 
Russell's blessing, this is the result.  It is apparently the basis for the Disney Version)
         Doctor Syn - Alias the Scarecrow by Vic Crume (1962?),
book for 8-12year-olds, based on the Disney version.

"DOCTOR SYN was reportedly conceived when Thorndike 
stayed up with his sister Sybil (later Dame Sybil), both of them 
actors, one night after they'd seen the body of a shooting 
victim in the street outside the theater where they'd both been rehearsing THE TEMPEST. The corpse seemed to stare up 
at Sybil's bedroom, preventing her from getting to sleep and 
thus keeping Russell up long enough, taking tea with her and discussing various gruesome topics, for Dr. Syn's sometimes gruesome career to be born. "

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