In 1976 David "the Edge" Evans, Paul "Bono" Hewson, Larry Mullen Jr. and Adam Clayton formed the Larry Mullen Band and then as "Feedback". In 1979 they managed to release their first EP titled "Three" and changed their name to U2. The EP isn't that great. 2 songs of that EP would end up on their debut album in better re-recorded versions.
Three - EP cover
In May 1980 U2 released "11 O'Clock Tick Tock". Their first international single and their debut on Island Records which failed to chart. Then they worked on 3 albums with producer Steve Lillywhite.  Normally he only produces 2 albums for an artist as a maximum but for U2 he made an exception.
Boy - album cover
Their debut album from 1980 "Boy" started with their first known hit titled "I Will Follow" in which we hear their magical style from the 80's. "Out of Control" was very dry and punky on their debut EP but the version on the debut album is much better. "A Day Without Me" was released as a single but failed to chart.

Best songs are: I Will Follow, An Cat Dubh, A Day Without Me, Electric Co.

Boy
I Will Follow / Twilight / An Cat Dubh / Into the Heart / Out of Control / Stories for Boys / The Ocean / A Day Without Me / Another Time, Another Place / The Electric Co. / Shadows and Tall Trees
October - album cover
The second album "October" from 1981 continued the style from the first album and even sounds better but in terms of lyrics it's lesser partly because Bono's lyric notebook was stolen from a backstage room during the tour for the first album. Opener "Gloria" displays some musical dynamism. "Tomorrow" is a beautiful ballad that gives Bono a chance to show his range and indicate that they were Irish made clear by Uilleann pipes. "With a Shout" tries to resemble "I Will Follow" but isn't as strong. "Fire" was the first single from the album and reached the charts in the UK. The single "Gloria" was U2's first song to have its music video played on MTV. During the tour for the second album they met dutch photographer Anton Corbijn who would become very important for their career since he made photographs for their singles and albums as well as other visuals.

Best songs are: Gloria, I Threw A Brick Through A Window, Fire, Tomorrow.

October
Gloria / I Fall Down / I Threw a Brick Through a Window / Rejoice / Fire / Tomorrow / October / With a Shout / Stranger in a Strange Land / Scarlet / Is That All?
New year's day - single cover
In between "October" and "War" they released the single "A Celebration" backed by "Trash, Trampoline and the Party Girl" aka "Party Girl" which made it to the live album "Under A Blood Red Sky" in 1983.
War - album cover
They did better on their third anti-war album "War" that started with "Sunday Bloody Sunday" named after the shooting of 26 civilian protesters by members of the 1st Battalion of the British Parachute Regiment in Derry, Northern Ireland in 1972. The energy of the opener continued with "Two Hearts Beat As One" and "New Year's Day" which are thrilling. "Surrender" features an early dose of the Edge's fractured slide guitar style. Seconds is about nuclear proliferation. Other themes on the album are prostitution (“Red Light”) and love (“Two Hearts Beat as One”). On the album closer "40" Bono returns to a refrain from "Sunday Bloody Sunday" saying "I will sing, sing a new song/ How long to sing this song".

Best song are: Sunday Bloody Sunday, Seconds, New Year’s Day, Two Hearts Beat As One, Surrender.

War
Sunday Bloody Sunday / Seconds / New Year's Day / Like a Song... / Drowning Man / The Refugee / Two Hearts Beat as One / Red Light / Surrender / "40"
I will follow - single cover
"Boy" and "War" became their most succesfull of this era also because of the fantastic covers starring Peter Rowen who is the young boy.
An Cat Dubh
Tomorrow
New year's day