11. An information processing method of composing an integrated electronic document, said method comprising: a holding step of holding a plurality of kinds of electronic source documents in a storage medium, each of the electronic source documents including a plurality of source pages; a selection step of selecting at least one desired source page from the plurality of source pages included in the plurality kinds of electronic source documents held in the storage medium in the holding step; a composition step of composing the integrated electronic document on the basis of at least one source page selected in the selection step, wherein the integrated electronic document is composed of link information that links to the selected source page, the selected source page being used as a page of the integrated electronic document; an editing step of controlling to edit and then overwrite with an edited source page, the source page in the electronic source document, wherein the source page has been used as a page of the integrated electronic document in said composition step; an input step of inquiring of a user an input of an instruction regarding updating the page of the integrated electronic document and deleting the page of the integrated electronic document in response to when the source page being used as the page of integrated electronic document is edited and then overwritten with the edited source page in the electronic source document by said editing means; and a control step of controlling, in the case that updating the page of the integrated electronic document is instructed by said user in said input step, the page of the integrated electronic document corresponding to the edited source page of the electronic source document with the edited source page edited in said editing step and controlling, in the case that deleting the page of the integrated electronic document is instructed by said user in said input step, deleting the page of the integrated electronic document corresponding to the edited source page of the electronic source document, wherein the edited source page of the electronic source document is not deleted when the page of the integrated electronic document corresponding to the edited source page of the electronic source document is deleted.
11. An information processing method of composing an integrated electronic document, said method comprising: a holding step of holding a plurality of kinds of electronic source documents in a storage medium, each of the electronic source documents including a plurality of source pages; a selection step of selecting at least one desired source page from the plurality of source pages included in the plurality kinds of electronic source documents held in the storage medium in the holding step; a composition step of composing the integrated electronic document on the basis of at least one source page selected in the selection step, wherein the integrated electronic document is composed of link information that links to the selected source page, the selected source page being used as a page of the integrated electronic document; an editing step of controlling to edit and then overwrite with an edited source page, the source page in the electronic source document, wherein the source page has been used as a page of the integrated electronic document in said composition step; an input step of inquiring of a user an input of an instruction regarding updating the page of the integrated electronic document and deleting the page of the integrated electronic document in response to when the source page being used as the page of integrated electronic document is edited and then overwritten with the edited source page in the electronic source document by said editing means; and a control step of controlling, in the case that updating the page of the integrated electronic document is instructed by said user in said input step, the page of the integrated electronic document corresponding to the edited source page of the electronic source document with the edited source page edited in said editing step and controlling, in the case that deleting the page of the integrated electronic document is instructed by said user in said input step, deleting the page of the integrated electronic document corresponding to the edited source page of the electronic source document, wherein the edited source page of the electronic source document is not deleted when the page of the integrated electronic document corresponding to the edited source page of the electronic source document is deleted. 13. The method according to claim 11 , further comprising: a display control step of controlling display of a first display window for displaying a thumbnail image of each source page of each electronic source document and a second display window for displaying a thumbnail image of each page of the integrated electronic document, wherein in the editing step, each page of the integrated electronic document is edited using the thumbnail image displayed on the first display window and the second display window, and wherein in the display control step, display contents of the second display window are updated on the basis of the editing result in the editing step.