In the late 1980s and much of the 1990s, annuals published by Marvel Comics and DC Comics were usually released in the summer of the year and often had a unifying theme, either a similar theme that individual stories were written around, or a crossover storyline bringing many of the characters in the individual publishers' continuities together for a single overall event. In the case of the "crossover" annuals, the number of characters and annuals involved in a crossover story varied. Some were company-wide, incorporating virtually every character in the publisher's shared universe whose series received an annual edition. Others used smaller groups of characters whose series had some sort of in-story connection, such as series featuring members of teams or "extended families" of characters.