Joy, sadness, dreams and politics are among the emotions and messages expressed in graffiti paintings and murals on the concrete walls of Gaza, captured in a recently published book on graffiti art in the strip.

"A thousand congratulations to the two bridegrooms," reads one graffiti painting in Arabic. Another hails the enclave's resistance fighters. "The martyr's stronghold" is written in broad Arabic letters on a wall in a similar black-and-white pattern as that of the Palestinian scarf, the Kuffiyeh. A third message written on a wall near a demolished building asks "Why??!!" in English.

The book, titled "Gaza Graffiti: Messages of Love and Politics," is written by Swedish photojournalist Mia Grondahl and explores the strip's vibrant and diverse graffiti art scene and how it has evolved over the years. Some of Grondahl's pictures are currently on display in a gallery at the American University of Cairo.

Grondahl told Babylon & Beyond that she became fascinated with the graffiti in Gaza and its messages back in the 1990s. In 2002, she began to document it .

According to the book, graffiti first began appearing in Gaza during the first Palestinian Intifada in 1987 as a means of communication and information due to the Israeli control of the media output in the enclave.

"The walls became the self-evident communication channel -- a place to create newspapers that could reach everyone in Gaza," said the book. "In graffiti, the Intifada's activists had found a way to inform Gaza residents about what was happening: The walls told them who had fallen in battle, summoned them to take part in new protests, and encouraged them to continue resisting."

One image in the book shows the two brothers Bahaa and Dia Qidra in the midst of putting the finishing touches on a large portrait of the senior Fatah political figure Marwan Barghouti, who was sentenced to a long jail term on accusations of murder in Israel a couple of years ago.

"They have turned our homeland into a prison and Marwan is in chains," reads a text in Arabic accompanying the mural.

Bahaa Qidra is presented in the book as one of most talented graffiti artists in the Gaza strip, commissioning paintings and murals for both Hamas and its political rival, Fatah. His largest graffiti project to date is a 22 meters high and 8 meters wide portrait of the former Palestinian leader Yassir Arafat, which arrayed the mourning tent erected in Gaza shortly following Arafat's death in 2004.

Arafat is still the most common Palestinian leader depicted on Gaza's concrete walls, according to Grondahl, and the year 2007 witnessed a surge in portraits of the veteran leader as a backlash to Hamas allegedly confiscating posters and materials that were to be used for the marking of the three-year anniversary of his death.

"When I heard that Hamas had confiscated posters and all other material ... I decided to paint Arafat all over Gaza," the book quoted 23-year graffiti artist Mohammad Dirri as saying. "Not even Hamas dares to destroy portraits of Arafat. Such an act would provoke anger," he continued.

Aside from Arafat, another figure that gained prominence on the walls of Gaza is Hamas founder Ahmed Yassin, who was assassinated in 2004 when an Israeli helicopter gunship fired a missile at the quadriplegic as he was was being wheeled to morning prayers.

In fact, the author believes Yassin would have been the most portrayed leader in Gaza had it not been for a Hamas ban in 2002 that called for the stopping of martyr portraits of young men who died in fighting with Israeli troops. The ban apparently also applied to senior Hamas leaders as the portraits of Yassin were washed off the walls as the ban went into effect. Today, there is only one remaining graffiti mural of Yassin which was painted on a hidden wall by an unknown artist near one of Gaza's poorest refugee camps.

Grondahl considers graffiti in Gaza as a kind of barometer of the political situation in the strip. New political messages and slogans appear on the walls almost on a daily basis, replacing old ones and also serving as a tool for measuring political influence between Hamas and Fatah.

"There is constant competition between the two organizations to reach the Palestinian people," artist Fayez Sersawi said in the book.

Though both organizations focus on putting out political messages, the styles used by Hamas and Fatah in their graffiti appeals are quite distinct from one another, Grondahl noted. While Fatah appears to her to be more concerned about the content, Hamas tends to focus more on the presentation and the artistry.

"Hamas has the most skilled calligraphy artists," she said. "Fatah thinks the content is most important."

But politics is far from everything adding color to Gaza's bleak, gray walls in the form of graffiti these days. Many messages scribbled on the walls speak of dreams and longing and expresses emotions, embodied in the wedding celebrations, the birthday congratulations, and the hope of one day living in peace and freedom.