Figure 37 is a highly linear voltage-to-frequency converter, based on a quartz-stabilized switched-current charge loop. Q=IT (see App Note 14). The 0 to 10-kHz range exhibits 0.0015% linearity. I surprised that the LTC1043 is that good as a current switch (since it is designed as a good voltage switch).
The rest of the circuits are power converters, covering a wide range of applications, most of them high-voltage regulators based on circuits from previous app notes.
Figure 40 is an LT3468 flashlamp circuit, simplified by removing the red-eye-reduction capability (see App Note 95). Figure 44 reuses the LT3468 flashlamp controller to implement a 0 to 300-V variable supply. Figure 46 improves the output-ripple voltage by including a discrete-linear-regulator design on the output (see App Note 32). Figure 48 is a 5V-to-200V switching regulator for APD biasing (see App Note 92). Figure 50 is a wide-range regulator that provides 0 to 500 volts at 100 watts of output power (see App Note 35).
The final circuit, in Figure 55, isn't a high-voltage circuit, but instead is a load-sharing scheme between two low-voltage linear regulators.
Appendix A briefly discusses bandwidth and rise time for high-speed measurements, and Appendix B discusses connectors, cables, adapters, attenuators, and probes for high-speed measurements.
The app note concludes with a cartoon. "It's dark in there. You can think about circuits."