Top rope soloing has been a climbing technique employed by climbers without partners for fifty years, allowing a climber to top rope climbs with a certain degree of safety lacking in free soloing. For various reasons, these techniques were never formally codified or documented for others to learn from or build upon; instead, they were passed on through word of mouth. One possible reason for this lack of formalization was the inherent risk associated with these techniques, making people hesitant to take responsibility for potential accidents. However, the advent of the internet changed this dynamic. Suddenly, the subject began to receive significantly more attention, both on climbing forums and websites, as well as on video platforms like YouTube. While this helped disseminate more information, it also created a problem: what was once a lack of information turned into an overwhelming abundance of it. Everyone was sharing their thoughts at once, leading to a mix of both bad and good advice. Simultaneously, there was a surge in interest in top rope soloing, accompanied by a corresponding increase in accidents. Something needed to be done to address this issue. "On the Line" was a three-year project aimed at consolidating all available information on the subject, both old and new, and integrating it with industrial rope access techniques. The goal was to finally produce a foundational text on the subject. It's important to note that "On the Line" is not meant to be the definitive authority on the subject but rather the first step in the right direction. Subjects covered include: Safety Device mechanics. Device selection. Device attachment Back-ups Rope systems (one rope, two ropes, pseudo leading, top rope TRS). Rigging. Escape. Re-anchors and redirects. Lots and lots of micro details on hardware and software.