Contact me before ordering. Although I can write on any topic, if I must read a book for the assignment I must agree that it is interesting before accepting the order. My preference is for scientific/technical topics, irrespective of whether they come wrapped up in a technical manual, romance novel or cutting-edge Science Fiction.
Three hundred words (more with extras below) as a general lead-in to more specific content for your e-book, referencing content and development.
Length of book will affect production time of the introduction, since I will have to read it (naturally).