The primary goal of this book is to provide practical guidance on the design of isolated DC–DC converters. In practice, this means that a design engineer receives the technical specifications for a power converter that they need to develop, along with cost targets based on the planned production volume per year. In the automotive industry, adhering to cost constraints is a strict requirement. This is the first step. After analyzing this information, the next step involves the power electronics design, which includes selecting the topology and power components to be used. The selection process requires choosing one topology from a list of options. This decision is crucial, as it significantly influences the overall success of the project. Having a list of comparative topologies is essential for making an informed choice. This principle is fundamental in engineering and proves very useful, which is why many publications provide comparisons of topologies based on various parameters. Some publications compare several topologies [1, 2], while others focus on three [3] or two [4]. A particularly good approach is to compare the application areas of a single topology [5] or a family of related topologies [6]. Generally, these comparisons are valuable and provide useful information, but they are often incomplete. Unfortunately, while some studies mention cost considerations [1, 4, 5], they often lack specific numbers and do not detail which parts of the converter contribute most significantly to the overall cost or why. Consequently, conclusions about the cost-effectiveness of a particular topology can be quite controversial [4]. Another important aspect is the technical specifications that the design engineer receives, which pertain to the application area. It’s highly preferable to understand the capabilities of a topology concerning the application and operating environment. For example, in references [7–9], the authors use data from a single implementation for their comparisons. If they mention the application, it indirectly indicates where this topology can be used [7]. All of this information is useful, but it is not comprehensive because it does not provide a complete view of the capabilities, operation, and application areas. Understanding the full range of a topology’s capabilities helps design engineers select the most suitable topology for the specific targets and requirements they have received.