Hellboy and the BPRD is a natural continuation of the main BPRD series which was set in the present but had covered the beginnings with BPRD: 1946, BPRD: 1947, and BPRD: 1948.

Spanning Hellboy and the BPRD: 1952 to 1957 these are mini-series, one for each year, starting with Hellboy's first mission in 1952. A young Liz Sherman makes an appearance and Trevor Bruttenholm is often around but none of the other regular characters appear so Hellboy is hanging out with human teammates, some from BPRD 1946 et al.

I like these stories as going back to more classic Hellboy: talking and investigating, monster appears, Hellboy punches it. Although occasionally someone dies these stories are lighter than the later Hellboy and really all related series set in modern times.

There's also a nice through-line about a secret US government organization competing with the BPRD. Whereas BPRD is mostly defense oriented "how to stop these creatures" this new organization wants to weaponize some of the BPRD research.

Overall a nice series and good change of pace to the regular series.