What is this im, iim, biii I have not a clue

Help I am lost. New to all this theory and starting to learn a bit just got a book but what it fails to tell me what the heck is the following

im, iim, biii, iVm can someone be kind as always to help me out and explain it as I have not a clue and hoping that someone has come across this

And later in the book it has im, bVi, bVii and im

Many thanks as always

I'm not entirely sure, as I didn't study music theory this way, and I think some of your numerals are wrong, but they are referring to chords formed on the scale degrees 1 to 7, in roman numerals. I'm almost certain that uppercase numerals, I, II, III, etc refer to major chords, and lowercase numerals or ones with an m in them are minor chords. And b means flat, so biii would be a minor chord starting from the minor 3rd of the scale - in C it would be Eb, Gb and Bb. Some of your numerals mix upper and lower cases, so you might want to check if they are written like that in the book.

B.H.S. hit the nail on its head. the b/# will be adjusting the interval/chord accordingly. The "m" refers to minor.

it means the first chord is a minor the second chord is a minor and the third is a flat

They're the roman numerals

I   = 1

II  = 2

III = 3

IV  = 4

V   = 5

VI  = 6

VII = 7

m stands for minor.
M stands for Major.
♭ stands for flat.
# stands for sharp.

To understand why there are even numbers, is because it's the notes used within a scale/key. Depending on the key, it can have many sharps or flats. There are a fair few lessons which go into this on this site, including mine.

To make it even easier...

Let's take C major,

C, D, E, F, G, A, B, C

Each note in this scale is given a degree. The roman numerals represent the degrees of the scale. So, for example, f is a IV. We use uppercase to represent Major chords, and lowercase to represent minor chords. So the E (Which is minor) is represented as Em, or iii. The G (which is major) is represented as G, or V.

This is a simple way to take music and transpose it to another key. So, let's say you are playing a 145 progression in C, (I, IV, V, or C, F, G). One of your band members says that the riff would be much easier to sing to if you played it in E major. Since all notes in the scale are relative, all you have to do is play a I, IV, V progression in E major (E, A, B, or I, IV, V) and you will get the same sort of feeling to the song, and you can have vocals!

C  Dm  Em  F  G  Am  Bdim

E  F#m G#m A  B  C#m D#dim

I  ii  iii IV V  vi  vii