The search for exoplanets and habitable objects in general is one of the fastest growing and most prominent fields in modern astrophysics. This book provides an overview on habitability on exoplanets. Habitability is strongly dependent on stellar activity. Therefore, space weather effects on objects in the solar system as well as on exoplanets are discussed.The concept of the book is to introduce the topics and then discuss actual scientific papers so that the interested reader has access to most recent research. Therefore the book is valuable to undergraduate students as well as to graduate students and researchers.