It's just a physics book that happens to have pictures of the popstar in it.
Anyway, it's kind of Ironic [1] that the dude from Queen is an astrophysicist, and Britney Spears is writing Semiconductor Physics tutorials. Something something music and math.
[1] Sorry
There’s some subtle bits to the humor depending on how charitable you’re feeling. It might just be absurdist, as in “Blackbeard’s guide to astrobiology”, or it may be more mean spirited and playing on a belief that she is not intelligent.
TL;DR - the joke formula is just:
subject=…
person_not_familiar_with_subject=…
joke=“${person_not_familiar_with_subject}’s guide to {subject}“
And the amount of implied cruelty in the comparison is variable.
https://en.wikipedia.org/wiki/Brian_May#Scientific_career
Maybe not so absurd.
Also, Todd Rundgren used to be a registered Apple developer. We'd see him moseying around the WWDC, every year.
Btw, she really went downhill once she fell out of popularity. I think she has a life put back together finally but she got a raw deal. I’m rooting for her.