Disclaimer: obviously this is my personal opinion, so don't flame me?

Every library has a 24/7 space that is a strict subset of the entire library that is open 24/7. When the library closes, students (and other members of the MIT community) must relocate to the 24/7 space to work. It's probably the only places that have security cameras or something so they know you're not destroying books or whatever collections they're hiding. Anyways, I distinguish between these two parts of the library, since I go to different libraries depending on whether or not they're open.

1. Rotch

It's one of the more niche libraries on campus, and a good amount of people are unaware of it. It's the architectural library, and so has displays about architectural stuff. The 24/7 space is on the first floor of the library, which is the second floor of the building (7). The higher floors consist of a walkway with rows and rows of bookshelves. Embedded in these bookshelves and overlooking the first floor of the library (it's kind of hard to describe), there are single cubicles to work in. Each cubicle is quite far apart from each other as well.

24/7 - It's quiet and there is a good amount of people. It's definitely not crowded, which is generally the case in the other libraries during 24/7.

Pros:

• way less people than the bigger libraries
• the cubicles in the upper floors are next to air circulation units that operate at a not-too-quiet hum. You can make noise without feeling super self-conscious. Sometimes I read aloud my math textbook (under my breath) because I can't understand the words otherwise, and the white noise from the machine helps mask the noise that I make.
• it doesn't matter anyways, because the cubicles are so hidden in the bookshelves that nobody would know that you are the one coughing every ten seconds.
• closest library to dorm row
• the architecture is industrialy and decently good looking

Cons:

• hosts less people in general
• no outlets in the cubicles, and I think there are generally less outlets
• not many group study places, and you can't be too loud in them because there aren't doors blocking them off
• I was once sitting on the 6th floor in a cubicle. There's a railing along the edge of the upper floors, and you can see the 2nd floor from it. My Apple Pencil slipped from my hand as I was twirling it around while thinking and it fell down the 4 floors. There's a crack on the outside of pen, but thankfully it still works.

2. Hayden

One of the big popular libraries that everyone goes to essentially. It looks modern, with floor to ceiling windows and colorful furniture against light-colored wood tables and white walls. There's a cafe on the first floor along with vending machines. There's even a courtyard next to it, though I'm not sure if I should attach it to Hayden. The 24/7 space is the first floor, though I haven't been to Hayden 24/7.

Pros:

• hands down the nicest looking library on campus. I love the colorful cloth seats paired with a light wood look of the tables
• tons of natural light
• good view of the Charles if you take one of the seats facing the window
• air vents provide a good hum of white noise
• tons of outlets
• group study pods with whiteboards and pretty good noise cancelling
• the cafe has really good food, though they seem to be out of half the things on their menu constantly
• there's a nap section? but I've never attempted to take a nap there, and I've never seen people do that.
• for some reason, I feel more motivated when I'm here. It's definitely the aesthetic and the natural light that helps. It's not just motivation, part of it is also inspiration. Maybe I should force myself into Hayden when I need to write a blog.
• longest hours out of all the libraries
• the guy who announces the closing of Hayden is so enthusiastic it makes me smile

Cons:

• there's a lot of people, and you'll have trouble finding a spot, especially on the first floor, even though there are a lot of spaces for you to be in.

Yeah, Hayden has basically no cons, but what's the point of having this great space if it's very hard for you to find a place to work in? That's why I don't have Hayden ranked first.

3. Lewis

It's the small music library right next to Hayden. It houses music scores and has tools to consume old-timey media. I think there isn't 24/7 space here?

Pros:

• cubicles have VCR tapes and record players and old fashioned TV's, and they're quite cute
• decent amount of natural light, though the light doesn't travel well to the upper floor
• less people
• has group study spaces, but the sound travels

Cons:

• lowkey musty
• cubicles are kind of small in terms of desk space because the media devices takes up a good chunk of the table. Well, they're wide but not deep.

4. Barker

The really famous dome in MIT is a library! The 24/7 space is the dome itself!
Pros:

• dome looks nice
• amazing chairs for naps, probably the most nappable library, also the library is dim, so even better
• has plenty of cubicles and rooms for you to work in
• plenty of tourists who come in and go "woaw mit students" (in their heads, I can hear them)

Cons:

• way too quiet, so much so that I feel like I will get kicked out for making sound louder than 10 decibels. I make a good bit of noise when I have my headphones in and I'm listening to music and I can't hear how loudly I flip through the pages of my notebook. I probably get judged by a lot of the people there.
• it's not just that it's quiet, it's also that it's a really boomy place, so any sound you make gets amplified.
• considerable lack of natural light
• walking through the scanner things at the entrance interferes with my bluetooth headphones and there's this loud high-pitched noise that plays and it hurts.

5. Dewey

The business library that's basically the furthest thing from the dorms. People don't generally come here because it's so far away from everything, and there are much nicer study spaces nearby (like Sloan). There are tons of old-looking dark-wood furniture.

Pros:

• so empty
• quiet, because there are so few people here
• it's on the side of campus that has the really cool city aesthetic
• plenty of food places nearby (notably the closest Starbucks to campus)
• there are a lot of study spaces
• it has the most group study rooms out of all the libraries, and since there are so little people, one of them is probably open. I took a nap in a study room with the lights off, and nobody disturbed me.
• plenty of outlets

Cons:

• literally on the other side of campus. It is literally a mile away from my dorm. The closest class I have to Dewey is still half a mile away. On the bright side, you can take the shuttle back.
• there's construction going on outside
• the tables have the old-looking aesthetic of worn wood
• looks old in general

Bonus: MacGregor study room
Pros:

• literally downstairs
• few people, and quiet
• two study rooms

Cons:

• only half the lights are on, so it's really dim
• small
• it gets quite hot in the winter