The variable X-ray sky requires wide–field monitoring with high sensitivity. We refer on novel X–ray telescopes with high sensitivity as well as large field of view. The results are very promising, allowing the proposals for space projects with very wide–field Lobster–eye X–ray optics to be considered. The novel telescopes will monitor the sky with unprecedented sensitivity and angular resolution of order of 1 arcmin. They are expected to contribute essentially to study and to understand various astrophysical objects such as AGN, SNe, GRBs, X–ray flashes, galactic binary sources, stars, CVs, X-ray novae, various transient sources, etc.