  We review the latest developments in our X-ray observational and theoretical
understanding of the outskirts of galaxy clusters, and their connection to the
cosmic web. The faint cluster outskirts are challenging regions to observe in
X-rays, requiring highly sensitive telescopes with low and stable background
levels. We present our latest understanding of the thermodynamic profiles of
clusters in the outskirts, and the biases that gas clumping and non-thermal
pressure support can introduce. Features in the outskirts due to merging
activity are discussed, along with the chemical enrichment of the outskirts
ICM. We describe future prospects for X-ray observations to explore further out
in the cluster outskirts and probe their connections to the cosmic web.
