Real image (such as the images on the right), real rays of light are always represented by full, solid lines; perceived or extrapolated rays of light are represented by dashed lines. A real image occurs where rays converge, whereas a virtual image occurs where rays only "appear" to converge. Real images can be produced by concave mirrors and converging lenses, only if the object is placed further away from the mirror/lens than the focal point and this real image is inverted. As the object approaches the focal point the image approaches infinity, and when the object passes the focal point the image
What If? (essays) lot of attention. What If? (essays) What If?, subtitled The World's Foremost Military Historians Imagine What Might Have Been, is a collection of twenty essays and thirteen sidebars dealing with counterfactual history. It was published by G.P. Putnam's Sons in 1999, , and this book as well as its two sequels, "What If? 2" and "What Ifs? of American History", were edited by Robert Cowley. It was later combined with "What If? 2" to form "The Collected What If?". Cowley decided to create the book after several "What if?" articles were published in the "Military History Quarterly", which he edits,