While trying to find more about the printing techniques used for early 19th century illustrated books such as Charles Dickens and thus the work of all illustrators who have worked in tandem with his creations, I came across this very interesting site which features a bit of history around each of the long line of these illustrators and their lives.
It makes it very clear that back then writer and illustrator had a very close working relationship which would thus produce great work, unlike the often unfortunate separation of writer and illustrator in today's publishing world.
Of note: Hablot Knight Browne adopted the moniker 'Phiz' that he is so well known for to complement Dicken's 'Boz' and was only hired once Robert Seymour (Dickens former illustrator) committed suicide. Once working together Phiz and Boz developed a great relationship, working together for 23 (!) year, until Phiz illustrated Dickens 'A Tale of Two Cities' which was a more serious story and did not complement his artwork, nor did his artwork complement the story. After this they never worked together again!
Also of note: George Cruikshank, another famous Dickens Illustrator apparently claimed that the plot and many of the characters from Oliver Twist were his idea after Dickens died. Very interesting. Of course this was strongly denied by Dickens friends, but why would this not be true? It is only natural that when two people work together on a project ideas are bound to be exchanged freely and so George Cruikshanks drawings for characters in particularly would have influenced Dickens greatly. It would be interesting to know what their collaborative process was. In other words, did they meet prior to Dickens having finished the story already. Did they bounce ideas off another. How often did Cruikshank usually have to change/alter his illustrations to satisfy Dickens etc...