While the illustrator will of course make some reference to the content of your manuscript, they will not necessarily read the book from front to back, nor will they choose the content of the illustrations.
As the author, you get full creative control and ownership of your illustrations, and therefore you get to decide how many illustrations you would like to include in your book, and what you would like those illustrations to depict. Of course, creating illustrations is an inherently creative and subjective process, and your illustrator will of course use their artistic discretion to fill in the gaps in your descriptions. After all, a picture is worth a 1000 words (or more)!
To start the illustrations process, your Project Manager will email you an Illustrations Questionnaire. You will use this questionnaire to carefully detail for the illustrator what you have in mind for the illustrations, and then your illustrator will use their expertise and creative judgement to create the initial sketch.
While our illustrators often read manuscripts for children’s books, or for other projects where the word count is very low, it is not part of your illustrator’s role or responsibilities to read your manuscript. Your illustrator will complete your illustrations based on the information you submit in the Illustrations Questionnaire. This is why we encourage our authors to take their time and be sure to complete their Illustrations Questionnaire in full, with all of the details they have in mind for each illustration.