Lewis Carroll/Mr. Dodgson and Mr. Carroll
Lewis Carroll generally guarded his "real life" identity of C. L. Dodgson very carefully. He went so far as to produce a printed notice known as the "Stranger circular" to that effect. When he received letters addressed to C. L. Dodgson, talking about Lewis Carroll, he returned them with this notice. It said, curtly, "Mr Dodgson . . . neither claims nor acknowledges any connection with any pseudonym or with any book not published under his own name."
Langford Reed and Evelyn Hatch 
Langford Reed, in his biography, goes so far as to suggest that he should be viewed as two people, "Professor" (sic) Dodgson, who wrote very boring books about mathematics, and Lewis Carroll, who wrote children's stories. In fact, this is a long way from the truth. There was plenty of totally serious stuff, and indeed some mathematics, published under the name of Lewis Carroll, and at least one fairly humorous work published as C. L. Dodgson. There was also quite a lot published under other pseudonyms.
Carroll's Friend Evelyn Hatch puts it another way in her collection of his letters (1933): "It is "Mr. Dodgson" who appears in these pages, a personality quite as unique and delightful as the author of Alice in Wonderland". This book is full of imaginative nonsense, some signed by "Lewis Carroll", some by "C. L. Dodgson" and, in one case, by both.
Mathematics and logic published by "Lewis Carroll" 
A Tangled Tale 
A Tangled Tale was a serial published in 1880-1 in ten parts, then reprinted as a book in 1885. It is an amusing story, or to be precise three stories which unfold and, in the last chapter, come together. Each episode told part of a story, and has embedded in it one or more maths puzzles. Contributors were invited to submit answers. He marked all these answers, which he graded as class I, II, III or fail, and published his solutions and criticisms of some of the answers received. The story itself is typically Carrollian. Some of the puzzles too are jokes, but most involve some serious mathematics. Thus this is clearly a piece of mathematical tutoring, as serious as any of the textbooks he wrote, as well as a Lewis Carroll novel.
In summary, this work clearly combines Carroll and Dodgson characteristics.
The Game of Logic 
The Game of Logic was published in a private edition in 1886 and in one for general sale in 1887. This is an attempt to teach formal logic to children by a game involving a board and counters. While there are clear traces of Carrollian humour in the logical propositions to be analysed, e.g.
- All Dragons are uncanny
- All Scotchmen are canny
- All Dragons are not-Scotchmen
- All Scotchmen are not-Dragons
it is basically a treatise on elementary logic.
Symbolic Logic 
Symbolic Logic, Part I was published in 1896 as a Lewis Carroll book. Carroll envisaged two further parts but never completed them. The available material was edited for publication by W. W. Bartley in 1977 (2nd edition 1986). This is a serious treatise on logic, which in recent years has come to be regarded as an important contribution to the subject. Again, there is plenty of lightheartedness in the propositions to be analysed, but on the "two person" theory it is a Dodgson work with only minor contributions from Carroll.
Serious works published by "Lewis Carroll" 
The pseudonym "Lewis Carroll" was not invented for the Alice books. Several years earlier, he had published several poems in a magazine called "The Train" under that name. Some of them - "Solitude", "The Path of Roses" and "The Sailor's Wife" - are totally serious poems. His last book, "Three Sunsets" (published just after his death), includes these and several other poems, nearly all serious.
Against Vivisection 
Carroll was a staunch opponent of vivisection. He published a letter "Vivisection as a sign of the Times" in the Pall Mall Gazette on 12 February 1875, and a substantial article "Some Popular Fallacies about Vivisection" in The Fortnightly Review on 1 June 1875. Ten years later, he returned to the subject with "Vivisection Vivisected" in The St. James's Gazette, 19 March 1885. All of these were serious arguments against vivisection. All were signed "Lewis Carroll".
Purity of Election 
On 4 May 1881 a letter appeared in St. James's Gazette, signed by Lewis Carroll, called Purity of Election. This is a totally serious attempt to suggest ways to avoid bribery and corruption in elections.
Euclid and his Modern Rivals 
This book was published in 1879 (2nd ed 1885) under the name of C. L. Dodgson. It is a discussion of the relative merits and demerits of a series of 19th century textbooks on geometry. How dull and boring - what could be better suited to Mr. Dodgson and further from Lewis Carroll? But there are many touches to this book that indicate the opposite. The whole book turns out to be the dream of an examiner, Minos (he and his colleague Rhadamanthus take their names from mythical Greek judges). Minos meets the ghost of Euclid, and a German professor called Herr Niemand (Mr. Nobody), evidently the twin of Mein Herr in the Sylvie and Bruno books. There are plenty of jokes, e.g. (p. 3)
- Minos: He might just as well say that a young lady, who was inclined to one young man, was 'equally and similarly inclined' to all young men!
- Rhadamanthus: She might 'make equal angling' with them all, anyhow.
And in a passage which clearly recalls the discussion in Through the Looking-Glass between the White King and Haigha about Nobody (p. 182):
- Niemand: The final list, was it? Well, ask your friend whether, since the drawing up of that list, any addition has been made: he will say 'Nobody has been added.'
- Minos: Quite so.
- Niemand: You do not understand. Nobody - Niemand - see you not?
- Minos: What? You mean -
- Niemand (solemnly): I do, my friend. I have been added to it!
- Minos (bowing) The Committee are highly honoured, I am sure.
- Niemand: So they ought to be, considering that I am a more distinguished mathematician than Newton himself, and that my Manual is better known than Euclid's! Excuse my self-glorification, but any moralist will tell you that I - I alone among men - ought to praise myself.
Can the author of that really be the humourless pedant that Mr. Dodgson has been portrayed as being?
Some other pseudonyms 
Lewis Carroll published works under several different pseudonyms. For example, he wrote several satirical pieces about events at Oxford University under the transparent pseudonym D. C. L. (a rearrangement of his initials). Some of these, such as "The New Method of Evaluation as Applied to Π" and "The Dynamics of a Parti-cle", involve quite a lot of mathematics. These works do not fit into the "two people" theory, unless we suppose that D. C. L. is a third person.