Thinness and ways to gain weight

Every disease has a cure... and the problem of thinness is easy and simple to treat... only if one knows its cause... is it hereditary or pathological? And if things get difficult, all you have to do, dear reader, is to browse the lines of this book, and, God willing, all horizons will open before you, and you will find within its folds all the solutions and you will reach the weight you desire. And you wish.