deepest without dungeon spell book?

[Pete Mack]

Level 60-65, IIRC. I was diving with priest-caster without rPois, and just crossing my fingers I wouldn't hit a drolem.

[PowerDiver]

My current rogue finally got MB4 at 3650'. At this point, I had only seen one other type of dungeon spell book, PB4 I think, don't know many as I squelch them as I see them. Unfortunately, I detected MB4 in a vault so ridiculously dangerous I wasn't even tempted, probably around 3000' but I don't really remember, so 3650' technically wasn't the first chance. This was in a playstyle killing plenty of drop_good monsters for CL 39.

Usually I get a dungeon spell book much earlier.

What's the deepest you've been when you saw or collected your first class-suitable dungeon spell book?