Help me with an adjective ...

I like 'luminescent' too

Is it a book on astronomy?

What section of the population is the book aimed at? Knowing that might help with the adjective you're searching for. Is it fact or fiction?

My mantra is always try to keep it simple

Spotlights

... as in throws a spotlight ...

swanny thanks for looking out for me , but I've the hide of a rhinoceros!

Thanks everyone, I've got there now...and I've learnt stuff.

and I meant as in the luminosity of stars .....

and I thought that 'coruscating' meant scathing and ultra-critical .....

back to the drawing board dictionary

I agree that you illuminate something when you shine a light on but luminous means giving off a light - like watches you can see in the dark; they had luminous hands and numbers.

Depending on what it illuminates you could use 'clarifies', 'elucidates' or 'reveals'

'on it' not just 'on'

coruscating: to give off or reflect light in bright beams or flashes : sparkle. 2 : to be brilliant or showy in technique or style.

well, well, well!!

jalima I suppose it would be a compliment to be described as having a coruscating wit.
Like you I had always thought it meant scathing.
I shall use it at the next opportunity

I'm another one who always thought 'coruscating' meant scathing or withering! You live and learn on GN!

gracesgran now I'm back with luminous in that case! Giving off light.

But does the text give off light or illuminate the subject?

Did the writing have certain "incandescent" quality to it?

I'm often incandescent, but usually with rage!

Dazzling? Glaring?

"Illuminating " if it sheds light surely. Luminous is something quite different.
"Incisive", "exhaustive" might do the job too.

You're not reviewing Torchy, Torchy The Battery Boy are you Grannyknot!

Teehee crafting no ...

Elucidates... shines a light / makes something clear ?